The measures of the angles of a triangle are shown in the figure below. Solve for x.

The Measures Of The Angles Of A Triangle Are Shown In The Figure Below. Solve For X.

Answers

Answer 1

Answer:

x = 6

Step-by-step explanation:

We know that the angles in a triangle add to 180°, so we can add the angles shown in this triangle together, make them equal to 180° and solve for x.

90° + (4x + 3)° + 63° = 180°

90° + 4x° + 3° + 63° = 180°

4x° + 156° = 180°

4x° = 24°

x = 6

So, x = 6. Hopefully, this helped! If you have any further questions, let me know.


Related Questions

find the value of x ​

Answers

Answer:

See below, please

Step-by-step explanation:

[tex](2x + 9) + (4x - 3) = 90[/tex]

[tex]6x + 6 = 90[/tex]

[tex]6x = 90 - 6 = 84[/tex]

Hence

[tex]x = 14[/tex]

12) Write the equation of a rational function
Vertical asymptote at x = 0 and x = -1
Horizontal asymptote at y = -4
Hole at x = 12
X-intercepts at x = 5, x=-7 L

Answers

Answer:

[tex] \frac{4(x - 5)(x + 7)(x - 12)}{(x + 1)(x)(x - 12)} [/tex]

Step-by-step explanation:

A rational function is

[tex] \frac{p(x)}{q(x)} [/tex]

where q(x) doesn't equal zero.

If p is a asymptote, or hole at that value, then we will use

[tex](x - p)[/tex]

Step 1: We have asymptote as 0 and -1 so our denomiator will include

[tex](x - 0)(x - ( - 1)[/tex]

Which is

[tex](x)(x + 1)[/tex]

So our denomator so far is

[tex] \frac{p(x)}{x(x + 1)} [/tex]

Step 2: Find Holes.

Since 12 is the value of the hole,

[tex](x - 12)[/tex]

is a the binomial.

This will be both on the numerator and denomator so qe have

[tex] \frac{(x - 12)}{x(x + 1)(x - 12)} [/tex]

Step 3: Put the x intercepts in the numerator.

Since 5 and -7 is the intercepts,

[tex] \frac{(x - 12)(x - 5)(x + 7)}{x(x + 1)(x - 12)} [/tex]

Step 4: Horinzontal Asymptotes,

Multiply the numerator and denomiator out fully,

[tex] \frac{ {x}^{3} - 10 {x}^{2} - 59x + 420 }{ {x}^{3} - 12 {x}^{2} + x - 12} [/tex]

Take a L

look at the coefficients,

Notice they have the same degree,3, this means if we divide the leading coefficents, we will get our horinzonral asymptote.

Multiply the numerator by 4.

[tex] \frac{4(x - 12)(x - 5)(x - 7)}{x(x + 1)(x - 12)} [/tex]

Above is the function,

Oxygen flows through one tube into a liter flask filled with air, and the mixture of oxygen and air (considered well stirred) escapes through another tube. Assuming that air contains 4% oxygen, what percentage of oxygen will the flask contain after 5 L have passed through the intake tube?

Answers

The amount of oxygen in the flask through the intake tube illustrates proportions

The flask 99.35% will contain of oxygen after 5L have passed through the intake tube

How to calculate the percentage of oxygen?

To do this, we make use of the following representations

P for the proportion of oxygenV for te volume of oxygenx for the proportion of oxygen in the flask after 5 L passed through

So. we have the following derivative

dP = dV - P * dV

Divide through by dV

dP/dV  = 1 - P

Next, we set up the integral

[tex]\int\limits^x_{0.040} \frac {1}{1 - P}dP= \int\limits^5_0 {dV}[/tex]

Integrate both sides

[tex]-\ln(|P - 1|)|\limits^x_{0.04} = 5[/tex]

Expand

-ln(|x - 1|) + ln(|0.04 - 1|) = 5

Evaluate the difference

-ln(|x - 1|) + ln(|-0.96|) = 5

Express as a fraction

ln(0.96/|x - 1|) = 5

Express both sides as exponents with a base of 2

e^ln(0.96/|x - 1|) = e^5

Solve for x

x = 1 - 0.96/e^5

Evaluate the difference

x = 0.9935

Express as percentage

x = 99.35%

Hence, the flask 99.35% will contain of oxygen after 5L have passed through the intake tube

Read more about proportions at:

https://brainly.com/question/1781657

In the diagram, the length of Line segment Y Z is twice the length of Line segment A Z.

Triangle X Y Z is shown. Angle X Y Z is a right angle. An altitude is drawn from point Y to point A on size Z X to form a right angle.

Line segment Y A is an altitude of ΔXYZ. What is the length of Line segment Y A?

5 StartRoot 3 EndRoot units
10 StartRoot 3 EndRoot units
15 units
20 units

Answers

Answer:

5 startrood 3 endroot units .

The length of YA from the figure is 10√3 units

Pythagoras theorem

According to the pythagoras theorem;

YZ² = AZ² + YA²

Given that YZ = 2AZ, hence;

20²  = 10² + YA²

YA²  = 400 - 100
YA²  = 300

YA = √300

YA = 10√3 units

Hence the length of YA from the figure is 10√3 units

learn more on Pythagoras theorem here:

https://brainly.com/question/343682

#SPJ9

how does the distributive property work

Answers

Explanation:

The distributive property tells you that multiplication distributes over addition. In equation form, it looks like ...

  a(b +c) = ab +ac

__

Groups and Multiples of Groups

The parentheses are a grouping symbol. In the above equation, they indicate that the sum (b+c) is to be treated as a group. When it is multiplied by 'a', everything in the group is multiplied by 'a'.

In the real world, there are many ways things are grouped. Baseball cards are packaged together with bubble gum; Cracker Jacks® are packaged together with a prize; left gloves are packaged together with right gloves; a bicycle is a package that has a frame, 2 wheels, a seat, handlebars. If you purchase a number of any of these packages, each of the items in the package is part of your purchase that number of times.

For example, 3 bicycles will have 3 frames, 3×2 = 6 wheels, 3 seats, 3 sets of handlebars. In algebraic form, this might look like ...

  3(f +2w + s + h) = 3f +6w +3s +3h

__

Eliminating Parentheses

Using the distributive property to eliminate parentheses is like regrouping the contents of the packages so like items are grouped together. In our above example, the 3 frames were grouped together when we considered that part of the group of 3 bicycles. The multiplier multiplies every member of the group.

__

Adding Parentheses

The reverse of the distributive property tells us we can regroup items into sets. It tells us we can take 3 frames, 6 wheels, 3 seats, and 3 handlebars and group them together in a way that makes 3 bicycles, each having a frame, 2 wheels, a seat, and handlebars.

  3f +6w +3s +3h = 3(f +2w + s + h)

Often, we're asked to choose the multiplier to be the greatest common factor (GCF) of the numbers of things in the group. That makes each group as small as possible. The multiplier only needs to be a common factor, not necessarily the greatest common factor.

18.
Given that sin x =
8
and sin y = , where x and y are acute, find the value of cos (x + y).
17
A.
B.
130
221
140
221
140
204
220
22
C.
D.

Answers

Answer:

B

Step-by-step explanation:

[tex]\sin{x}=\frac{5}{13}, \cos{x}=\sqrt{1-(\frac{5}{13})^2}=\frac{12}{13}[/tex]

[tex]\sin{y}=\frac{8}{17}, \cos{y}=\sqrt{1-(\frac{8}{17})^2}=\frac{15}{17}[/tex]

[tex]\cos(x+y)=\cos{x}\cos{y}-\sin{x}\sin{y}\\=\frac{12}{13}\times\frac{15}{17}-\frac{5}{13}\times\frac{8}{17}\\=\frac{140}{221}[/tex]

The equation to model Exponential Growth is:
y= a(1+r)*
y= total amount
a= starting amount
r= the growth rate as a decimal
t= number of growth periods
Question 2 (1 point)
You have been gotten a job offer and the company wants to start you out at $45,000
and will give you a 5% raise every year. Write an equation you could use to
determine how much you would be making after x number of years.

Answers

Your salary in x years is modeled an the exponential growth

The equation that determines your salary in x years is y = 45000(1.05)^x

How to model the salary growth?

The model of the exponential growth is given as:

y = a(1 + r)^x

From the question, we have:

Initial salary, a = 45000

Raise, r = 5%

So, the equation becomes

y = 45000(1 + 5%)^x

Evaluate the sum

y = 45000(1.05)^x

Hence, the equation that determines your salary in x years is y = 45000(1.05)^x

Read more about exponential functions at:

https://brainly.com/question/11464095

6 · 6 · 6 · 6 = 1,296. Using exponents, write two more expressions that also have a value of 1,296.

Answers


36^2 = 1296
1296^1 = 1296

Given that the width is 4.5 units and the length can be represented by x + 3, which answer choice shows the correct expression of the area below?
Please just explain step by step how you got the answer.
!!! I WILL GIVE YOU 50 POINTS IF YOU SOLVE IT!!!

Answers

Step-by-step explanation:

the area of a rectangle is

length × width

that is in our case

(x + 3) × 4.5 = 4.5x + 4.5 × 3 = 4.5x + 13.5

remember, when multiplying 2 expressions, you multiply every term of one expression by every term of the other expression and then you add all these individual results up by considering the signs, of course.

Eva filled a bucket with 7 gallons of water. A few minutes later, she realizes only 1 3/5 of water remained. How much water had leaked out of the bucket?

Answers

Answer:

[tex]6 \frac{2}{5}[/tex]

Step-by-step explanation:

[tex]7 - 1 \frac{3}{5} = 6 \frac{2}{5}[/tex]

Marcus has 127 baseball cards in his collection. Gabriel has 56 cards in his collection. Gabriel divides his collection evenly among Marcus and 7 other friends. How many baseball cards does Marcus have now?

Use the drop-down menu to show the correct answer.

Marcus has
Choose...
baseball cards now.

Answers

Answer:

134

Step-by-step explanation:

Gabriel has 56 cards and divides them evenly among 8 friends, which means each person has 56/8= 7 cards.

So Marcus has 127 + 7 = 134 cards

>> The total cost of a pizza and 3 drinks is $19. The price of the pizza is $10 and each drink is the
same price, d.
Which model represents the situation?
10
d
d
d
19
.) What is the price of one drink?
d
?

Answers

Answer:

d = 3

Step-by-step explanation:

According the figure:

10 + d + d + d = 19d = 3

Answer Check Below:

⇒ 10 + 3 = 13

⇒ 13 + 3 = 16

⇒ 16 + 3 = 19

Therefore, d = 3.

Answer:

$3

Step-by-step explanation:

⇒ 10 + 3d = 19 is represented by the figure⇒ 3d = 9⇒ d = 3The price of one drink is $3

A train leaves Philadelphia at 2:00 PM. A second train leaves the same city in the same direction at 4:00 PM. The second train travels
52 mph faster than the first. If the second train overtakes the first at 6:00 PM, what is the speed of each of the two trains?

Answers

Answer: First train speed shall be 42 mi/hr

Second train speed shall be 84 mi/hr

Yes it is the valid answer, it gets annoying when almost everyone enters the wrong answer for a good laugh. Either way, hope this helps! Have a spectacular day.

Step-by-step explanation:

What is the 1st train's head start in miles?

Let +s+ = the speed of the 1st train in mi/hr

From 2PM to 4PM is 2 hrs

+d%5B1%5D+=+s%2A2+

---------------------

Let +d+ = distance the 2nd train travels until

it overtakes the 1st train

From 4PM to 6PM is 2 hrs

Start time when the 2nd train leaves

---------------------

Equation for 1st train:

(1) +d+-+2s+=+s%2A2+

Equation for 2nd train:

(2) +d+=+%28+s%2B42+%29%2A2+

--------------------

Substitute (2) into (1)

(1) +%28+s%2B42+%29%2A2+-+2s+=+s%2A2+

(1) +2s+%2B+84+-+2s+=+2s+

(1) +2s+=+84+

(1) +s+=+42+

and

+s%2B+42+=+42+%2B+42+

+s+%2B+42+=+84+

------------------

The 1st train's speed is 42 mi/hr

The 2nd train's speed is 84 mi/hr

---------------------------

check:

(2) +d+=+%28+s%2B42+%29%2A2+

(2) +d+=84%2A2+

(2) +d+=+168+

and

(1) +d+-+2s+=+s%2A2+

(1) +d+-+2%2A42+=+42%2A2+

(1) +d+=+84+%2B+84+

(1) +d+=+168+

what is a question that is easier to answer using a stem-and-leaf plot than a dot plot?

Answers

Answer:

steam plot

Step-by-step explanation:

because the stem plot is easy to use

Answer:

When you use large numbers and don't have categories.

Step-by-step explanation:

Take these: 23, 27, 29, 35, 36, 41, 47, 48, 52. It is better as a stem and leaf.

---------------------------------------------------------------------------------------------------------

2 ][ 3 7 9

3 ][ 5 6

4 ][ 1 7 8

5 ][ 2

---------------------------------------------------------------------------------------------------------

If you use dot plot, it is recommended use amounts under 10.

Evaluate 3x2−9
when x=−2

Answers

Answer:

3

Step-by-step explanation:

substitute x = - 2 into the expression

3x² - 9

= 3(- 2)² - 9

= 3(4) - 9

= 12 - 9

= 3

164 hundreds - 12 hundreds

Answers

Answer:

152 hundred

Step-by-step explanation:

164 hundred - 12 hundred = 152 hundred

Please rate!

Answer:

1.52

Hope this helps :)

Step-by-step explanation:

step one:

put them as decimals which would be 1.64 and 0.12

step two:

subtract which would be 1.64 - 0.12

step three:

solve your answer would be 1.52 or 152 hundredths

i need help on a math question thank u

Answers

Answer:

XZ is longer than XY

Step-by-step explanation:

First we can notice all of the answers consist of knowing the lengths, so we must now find the lengths for each segment. To do this, we must use the pythagorean theorem.

(1, -1) and (-5, -5)

-5- -1 = -4

-5-1 = -6

-4^2+-6^2 = c^2

16+36 = c^2

52 = c^2

7.21110255 = c

So, the length of XZ is 7.21110255 units long

(1, -1) and (8, -2)

8-1 = 7

-2--1 = -1

7^2+-1^2 = c^2

49+1 = c^2

50 = c^2

7.07106781 = c

So, the length of XY is 7.07106781 units long.

XZ is longer than XY

a recipe for 5 people calls for 1.5 kg of meat. How much meat is required if the receipe is adapted to feed 8 people​

Answers

Answer:

2.4 kg

Step-by-step explanation:

1.5 divided by 5 is 0.3 and 0.3 multiplied by 8 is 2.4

If log_10(x) = 3 + log_10(y), then find x/y

Answers

Answer:

 1000

Step-by-step explanation:

[tex]log_{10}x = 3 + log_{10}y[/tex][tex]log_{10}x - log_{10}y = 3[/tex][tex]log_{10}(x/y) = 3[/tex][tex]x/y = 10^3[/tex][tex]x/y = 1000[/tex]

Answer:

  x/y = 10^3 = 1000

Step-by-step explanation:

The rules of logarithms tell you ...

  log(x/y) = log(x) -log(y)

__

Here, we have ...

  log(x/y) = log(x) -log(y)

  = (3 +log(y)) -log(y) = 3 . . . . . . . . substittute for log(x)

Taking the antilog, we get ...

  log(x/y) = 3

  x/y = 10^3 = 1000

_____

Additional comment

The expression log(x) is often used to refer to the "common log" of x, which is the logarithm to the base 10. This lets us avoid the cumbersome notation log_10(x).

In more formal mathematics, log(x) may be used to refer to the natural log. The distinction is usually made in high school algebra by referring to the natural log using ln(x).

For a class activity, a teacher put students into teams of 5. The teams were made up of 2 students randomly chosen from group A and 3 students randomly chosen from group B.

If group A has 4 students and group B has 6 students, how many different team combinations were possible?

Enter your answer as a number, like this: 42

Answers

Answer:

120

Step-by-step explanation:

6p3 = 120

The number of the different combinations of the teams will be 26.

What are permutation and combination?

A permutation is an act of arranging objects or numbers in a particular order. Combinations are a method of selecting objects or numbers from a group of objects or collections without regard for their order.

Given that for a class activity, a teacher put students into teams of 5. The teams were made up of 2 students randomly chosen from group A and 3 students randomly chosen from group B. If group A has 4 students and group B has 6 students,

The number of possible combinations will be calculated as,

C = ⁶C₃ + ⁴C₂

C = ( 4 x 3 ) / 2 + ( 6x 5 x 4 ) /( 3x 2 )

C = 6 + 20

C = 26

To know more about permutation and combination follow

https://brainly.com/question/4658834

#SPJ2

A 40-kilogram bag of seed is spread evenly about the entire yard. How much, in kilograms, of the seed will NOT be watered? Use: Percentage = watered squares / Total # of Square X 100

Answers

The computation of the percentage shows that the kilograms of seed that won't be watered is 12 kilograms.

How to calculate the percentage?

Your information is incomplete. Therefore an overview will be given. Let's assume that the watered squares are 35 while the total squares are 50.

Then, the percentage of the watered squares will be:

= 35/50 × 100

= 70%

Therefore, the percentage of the unwatered squares will be:

= 100% - 70%

= 30%

Then, the kilograms of the seed that won't be watered will be:

= Percentage of unwatered seed × Entire kilograms of seed

= 30% × 40kg

= 12kg

In conclusion, the seed that won't be watered is 12 kg.

Learn more about percentages on:

https://brainly.com/question/24877689

10ft,10ft,4ft what is the area

Answers

Answer:

400 ft sq

Step-by-step explanation:

Area = Length x Width x Height

10 x 10 x 4

100 x 4

400

Have a great day!!

Please rate and mark brainliest!!

400 ft^2………………………………

José plotted points on a coordinate plane to represent the vertices of a rectangle. The first
two points José plotted are shown below.

Answers

Jose's rectangle must have equal and parallel opposite sides

The coordinates of the other points could be C(7,5) and D(7,1)

How to determine the other points?

The coordinates are given as;

A = (2,5).

B = (2,1).

To form a rectangle, each of the remaining points must have the same y-coordinates as points A and B.

So, we have:

C = (x,5)

D = (x,1)

Also, the remaining points must have the same x-coordinates.

i.e.

Cx = Dx

From the list of options, we have:

C(7,5) and D(7,1)

Hence, the coordinates of the other points could be C(7,5) and D(7,1)

Read more about rectangles at:

https://brainly.com/question/12500692

Whats the value of the question

Answers

Answer:

8

----

125

Step-by-step explanation:

(2/5)³

2      2     2          8

--- x --- x ---  =  ---------

5      5     5         125

I hope this helps!

3. You want to have $4000 in your savings account after 2 years. Find the amount you should deposit for each of the situations described below. a. The account pays 3% annual interest compounded monthly. b. The account pays 4% annual interest compounded continuously.​

Answers

Answer:

Part A)

About $3767.34.

Part B)

About $3692.47.

Step-by-step explanation:

Part A)

Recall that compound interest is given by the formula:
[tex]\displaystyle A = P\left(1+\frac{r}{n}\right)^{nt}[/tex]

Where A is the final amount, P is the initial amount, r is the interest rate, n is the number of times compounded per year, and t is the number of years.

To obtain $4000 after two years, let A = 4000 and t = 2.

Because the account pays 3% interest compounded monthly, r = 0.03 and n = 12.

Substitute and solve for P:

[tex]\displaystyle \begin{aligned} (4000) & = P\left(1+\frac{(0.03)}{(12)}\right)^{(12)(2)} \\ \\ P & = \frac{4000}{\left(1+\dfrac{(0.03)}{(12)}\right)^{(12)(2)}} \\ \\ & \approx \$3767.34\end{aligned}[/tex]

In concluion, about $3767.34 should be deposited.

Part B)

Recall the formula for continuous compound:

[tex]\displaystyle A = Pe^{rt}[/tex]

Where e is Euler's number.

Hence, let A = 4000, r = 0.04 and t = 2. Substitute and solve for P:

[tex]\displaystyle \begin{aligned}(4000) & = Pe^{(0.04)(2)} \\ \\ P & = \frac{4000}{e^{(0.02)(4)}} \\ \\ & \approx \$3692.47 \end{aligned}[/tex]

In conclusion, about $3692.47 should be deposited.

A company interviewed 21 applicants for a recent opening. Of these applicants, 7 wore blue and 6 wore white, while 5 applicants wore both blue and white. What is the number of applicants who wore neither blue nor white?
A.1
B.6
C.12
D.13

Answers

Answer: D

Step-by-step explanation:

21=7+6+neither-5

7+6=13-5=8

21-8=13

hey guys can you please help me with these questions​ please explained them

Answers

B for question 12

B for question 13

Step-by-step explanation:

U = Union

n= intercestion

B'= not b

A"= not a

so AnB'

should be B

if 2.50 = 1

2.50x8=

20

1×8 =

8

should be $8

Solve and verify your answer.
A sludge pool is filled by two inlet pipes. One pipe can fill the pool in 11 days and the other pipe can fill it in 24 days. However, if no
sewage is added, waste removal will empty the pool in 32 days. How long (in days) will it take the two inlet pipes to fill an empty pool

Answers

Answer:

' =9 93/107 days

Step-by-step explanation:

1/11+1/24

one day =35/264

35/264 -1/32

=107/ 1056- fraction of rem in a day

1 day= 107/1056

x = 1

=107/1056x=1

x=1÷107/1056

1056÷107

=9 93/107 days

What is the solution to use the following equation 5(2x-6)+20=10

Answers

Answer:

first you distribute the five making it 10x-30+20=10

second you combine like terms making it 10x-10=10

third you isolate the variable making it 10x=20

Finally you divide both terms by ten giving you x=2 as your answer.

Calculate the determinant of this matrix:
What is the first step?

Step 1: Augment the matrix by copying columns 1 and 2 to the right of the matrix

Step 2: Find the products along the main diagonals
d1= 4
d2= 0
d3= 3

Step 3: Find the products of the minor diagonals
e1= 0
e2= 16
e3= 2

Step 4; Perform the final calculation

d1+d2+d3-e1-e2-e3= -11

(Got them all right on edge 2022)

Answers

Why did you ask this, but also answer it?- Lol thank you for the points though I guess...

Answer:

thank you they are all correct!

Step-by-step explanation:

Other Questions
What is the definition of a communicable disease?any disease that spreads from person to personany disease that spreads from person to person, , , ,any disease that triggers a high fever in a hostany disease that triggers a high fever in a host , ,any disease that must infect a host to surviveany disease that must infect a host to survive , ,any disease that can be treated with antibiotics How do nutritional needs change over time? Is (3, -5) a solution to this system of equations?y = -1/3x - 4 y = -2x + 1Yes or No Sontonca Structuro 15Worksheet 10Practice With Sentence StructureHomeworkThis page gives practice with concepts from Workshoote 1-9.1. Writo whether each word group is a fragment (F), sentonco (S), or run-on error (RO). If it is a sentenceor a run-on error, underlino oach simple subjoct once and each simple predicate twice.a. Martin Luther was born in Eisleben, Germany, on November 10, 1483.b. The son of Hans and Margaret Ziegler Luther.c. Why did this man devote himself to religion he had studied law at first.d. Luther was caught in a thunderstorm and was dashed to the ground by lightning.o. He renounced the world and became a monk, later he became a Reformation leader.2. In exerciso 1, find the two words where each run-on error should be divided. Write those words withcorrect punctuation and capitalization,3. Diagram the skeleton of each sentence.a. Luther opposed the sale of indulgences.b. He posted his objections on a church door. How does sherlock holmes discover about the hound of the baskervilles if 192 students are in 4 buses how many students are in each bus? Need Help Asap please. Question 1) Describe how the nervous system helps different parts of your body communicate with one another the moment you begin to pet a dog. ( Please make sure you answer this question completely and right). Will Mark Brainliest if answered correctly. Write a much as you can. What are two reasons why propaganda works to mobilize the people of a nation. Marketing analysis determined 55% of females between the ages of 25 to 34 years old search for green technology and practice being green, as compared to 33% of men in the same age group. What is the probability that a randomly selected man between the age of 25 and 34 does not search for green technology A pendulum bob has it maximum speed at 3ms at the lowest position 0. Calculate the height of the bob above 0,where it velocity is 0 Find the value of x.log x 8 = 0.5.4.OB.16O C.32OD.64 Which of the following would not be a good reason to use a linear model?Thank Which major event of the Spanish-American War occurred in the Philippines? explain what happened to Emmet Till Please help me!!!!!!!!!!! I really need help Look at the five words you selected to study during this lesson. Use the fourth one in an original sentence. In a second sentence, explain how you have used this word in your daily life. In a third sentence, explain where you have heard or read this word. Use proper grammar and spelling. Note: You must write your own original sentence to receive points for this question. (6 points) Write a word problem to match the shaded fraction bar 3/4 Find the function value f(1) if f(x) = x + 3 Step by step please Environmental occurrences such as floods or hurricanes can change history