Write an equation of each sentence. Use n to represent the unknown number. You can use the back page for your solution. (2 points each) 11. Six increased by a number is twenty. 12. A number decreased by seven is four. 13. The sum of two consecutive numbers is thirty-one. 14. The sum of twice a number and two is thirteen. 15. One less than a number is eighteen. 16. The square of a number increased by four is twice the number. 17. Twice a number is one-half. 18. The product of a number and its half is eighteen. 19. The average of a number and ninety is seventy. 20. Two more than a number is twelve.

PLEASE HELP Me​

The dimensions of the circle and square that produce a minimum total area are 1.12 and 2.24 respectively

Represent the side length of the square with s, and the radius of the circle with r.

So, the perimeter (P) and the area (A) of the shape are:

[tex]P =4s + 2\pi r[/tex]

[tex]A =s^2 + \pi r^2[/tex]

The perimeter is 16. So, we have:

[tex]4s + 2\pi r = 16[/tex]

Divide through by 4

[tex]s + 0.5\pi r = 4[/tex]

Make s the subject

[tex]s = 4 - 0.5\pi r[/tex]

Substitute [tex]s = 4 - 0.5\pi r[/tex] in [tex]A =s^2 + \pi r^2[/tex]

[tex]A = (4 - 0.5\pi r )^2 + \pi r^2[/tex]

Expand

[tex]A = 16 - 4\pi r + 0.25(\pi r)^2 + \pi r^2[/tex]

This gives

[tex]A = 16 - 4\pi r + (0.25\pi^2 + \pi )r^2[/tex]

Differentiate with respect to r

[tex]A' = 0 - 4\pi + 2(0.25\pi^2 + \pi )r[/tex]

[tex]A' = - 4\pi + 2(0.25\pi^2 + \pi )r[/tex]

Set to 0

[tex]- 4\pi + 2(0.25\pi^2 + \pi )r =0[/tex]

Add 4pi to both sides

[tex]2(0.25\pi^2 + \pi )r =4\pi[/tex]

Divide both sides by 2

[tex](0.25\pi^2 + \pi )r =2\pi[/tex]

Make r the subject

[tex]r =\frac{2\pi}{(0.25\pi^2 + \pi )}\\[/tex]

Factor out pi

[tex]r =\frac{2\pi}{\pi(0.25\pi + 1 )}[/tex]

Cancel out the common factors

[tex]r =\frac{2}{0.25\pi + 1 }[/tex]

Express pi as 3.14

[tex]r =\frac{2}{0.25\times 3.14 + 1 }[/tex]

[tex]r =\frac{2}{1.785}[/tex]

Divide

[tex]r =1.12[/tex]

Recall that:

[tex]s = 4 - 0.5\pi r[/tex]

This gives

[tex]s =4 -0.5 \times \pi \times 1.12[/tex]

This gives

[tex]s =4 -0.5 \times 3.14 \times 1.12[/tex]

[tex]s =2.24[/tex]

Hence, the dimensions of the circle and square that produce a minimum total area are 1.12 and 2.24 respectively

Read more about minimum areas at:

https://brainly.com/question/6427280

Answer:

Step-by-step explanation:

12 cars in 15 hours how many cars is in 10 hours

12 : 15 = x : 10

x = 12 * 10 : 15

x = 8

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

check

12 : 15 = 8 : 10

0.8 = 0.8

the answer is good

how many 2/3 are in 9/8?

or another way to put it will be

how many times does 2/3 go into 9/8?

well, is simply a division.

[tex]\cfrac{9}{8}\div \cfrac{2}{3}\implies \cfrac{9}{8}\cdot \cfrac{3}{2}[/tex]

its d becuase i used math-way

Step-by-step explanation:

b

=

4

Answer:

Step-by-step explanation:

Given equation:

Add 12 to both sides:

Correct graph is D, where point 4 is marked

Answer:

can't see the pic properly

Answer:

$2

Step-by-step explanation:

To use a percent you must change it to a decimal.

8% is .08

To find 8% of 25, we use multiplication.

.08 × 25

= 2

In case you cannot use a calculator or you want to be very quick about this, or just do a simple check... you can actually reverse the number (money, amount, etc) and the percent.

25% of 8 is not bad for doing mental math. 25% is a quarter, or 1/4 of 8 which again is 2.

Answer:

i think its B.

Thats only i know

Answer:

Step-by-step explanation:

So 4 cakes = 6 sugars, right so try taking it slow and think to yourself, 3=? then take it even slower until you go to 1=0.67 repeated

[tex]\dfrac 25(d-10) - \dfrac 23(d+6)\\\\\\=2 \left(\dfrac{d-10}5 - \dfrac{d+6}3 \right)\\\\\\=2\left[\dfrac{3(d-10) - 5(d+6)}{15}\right]\\\\\\=2 \left( \dfrac{3d-30-5d-30}{15} \right)\\\\\\=2\left(\dfrac{-2d-60}{15} \right)\\\\\\=2(-2) \left(\dfrac{d+30}{15} \right)\\\\\\=-4 \left(\dfrac{d+30}{15} \right)\\\\\\=-4\left(\dfrac d{15} +2 \right)\\\\\\=-\dfrac{4d}{15}-8[/tex]

Answer : 115,200

Step - by - step explanation :

sorry if this is wrong !

127,600 --> 128,000

0.93 --> 0.90

128,000 x 0.90 = 115,200

Answer:

x = 13

Step-by-step explanation:

180-52=10x-2

130=10x

13=x

Answer:

0.14

Step-by-step explanation:

brainliest please

Answer:

112+24x

Step-by-step explanation:

2(16+(10*4)+(x*12))

solve the inner bracket

2(16+40+12x)

solve this bracket

2(56+12x)

solve this now

112+24x

Answer:

[tex]24x+112[/tex]

Step-by-step explanation:

First of all we will start with the brackets inside the equation,

1. [tex]2[16+40+12x][/tex]

Now we can multiply 2 by all the values inside the parentheses

2. [tex]32+80+24x[/tex]

I just wanted to confirm that the big X is a variable?

Fact: Did you know that there are about 4 types of parenthese: ( ) - round brackets, [ ] - square brackets, { } - curly brackets, and < > - angle bracket.

Answer:

17/18

Step-by-step explanation:

To add fractions, you need to have common denominators. (4/9)*(2/2)=8/18.

Now that they have common denominators, you can add 8 and 9 to get 17. So, the answer would be the second one, 17/18.

Answer:

r u just cheating ur way through a whole test lol

Step-by-step explanation:

its B or 17/18

Answer:

The correct answer is C

x² - 2x -15

Answer:

4

Step-by-step explanation:

4 sets of strings will cost:

4×5=20

He will have $2 left over. Not enough to buy another set.

Or 5x<=22 DIVIDE BOTH SIDES BY 5

x <= 4.4 since he cannot buy .4 sets (this is a fraction of a set) He can only buy 4 sets

Answer: Emman is telling the truth because no one is saying that he is telling a lie.

Step-by-step explanation:

Answer:

The number 9490 is called the numerator or dividend, and the number 5 is called the denominator or divisor.

The quotient of 9490 and 5, the ratio of 9490 and 5, as well as the fraction of 9490 and 5 all mean (almost) the same:

9490 divided by 5, often written as 9490/5.

Read on to find the result of 9490 divided by 5 in decimal notation, along with its properties.

Answer:

x=65

Step-by-step explanation:

y= 23213

Answer:

100% if you have 8 boys in a row the change that three boys will sit next to each other is 100%

Hope This Helps!!!

Answer:

i think probably 3/28 ,that 3 boys will sit together

Answer:

All the mentioned can be constructed with the help of piling method. But, for construction of B and D we need a point as well.  

Please give brainliest only need 3 more brainliest before next rank!

Step-by-step explanation:

a) Yes, a cube can be formed by stacking polygons. If we stack squares one upon another, then the resulting 3-D figure would be a cube.

b) Yes, a cone that does not include the point can be made by stacking disc. If we stack discs such that the discs are arranges in descending order then the resultant 3-D figure would be a cone that does not include a point.

c) Yes, a pyramid can be formed by stacking polygons.

If we stack squares such that they are arranged in descending order of their side length and stacked by a point on the top. Then the resultant figure would be a  pyramid that includes a vertex.

f) There are many types of prism. Fro example a rectangular prism can be constructed by simply stacking rectangle polygon on one another.

e) Yes, a cone can be formed by stacking disc.

We need to stack disks arranged in descending order of their radius stacked with a point on the top. The resulting figure would be a cone that includes a point.

f) Yes, a cylinder can be formed by stacking. We need to stack discs of same radius to get a cylinder.

Answer:

B and D

Step-by-step explanation:

Answer:

a

Step-by-step explanation:

a

Answer: 1/5, 6/5, 11/5.

Step-by-step explanation:

1/5 is the smallest, as it isnt even 1 whole! (5/5)

6/5 = 1 1/5.

11/5 = 2 1/5, so its the greatest

Step-by-step explanation:

9+(-5)=4

-8-4=-12

8-(-4)=12

-9+5=-4

Hope this helps, just go connect the equation to the answer that I put.

RULES

If you have a minus and a minus (- -) it is equal to +

If you have Plus and Minus (- +) it is equal to -

The first one when simplified is 9-5=4

The second one Simplified is -8-4=-12

The third one simplified is 8+4=12

The fourth one simplified is -9+5=-4

I hope this helped and that you got the concept. If you have questions, ask me

Ps. If you mark me branliest it would-be very appreciated

Answer:

3 (B)

Step-by-step explanation:

rise/run

rise=3

run=1

3/1=3

Answer:

SAS

Step-by-step explanation:

there are vertical angles in the middle and the sides are already marked

Answer:

[tex]8\sqrt{2}[/tex]

Step-by-step explanation:

To find the length of an isosceles triangle, you know that the angles of the triangle are 45-45-90, so let's use that triangle theorem.

Therefore, the length of the hypotenuse (BD) is [tex]x\sqrt{2}[/tex], and x is equal to 8 (length of BC).

[tex]x\sqrt{2}[/tex]

x=8

Therefore, [tex]8\sqrt{2}[/tex] would be the length of side BD.

Answer:

oh snap i have this question too sorry cant help :(

Step-by-step explanation:

but i can provide with advice bc is the side down and bd is across us this to your advantage

Step-by-step explanation:

Relation

Hope it correct!!!

Answer:

D

Step-by-step explanation:

(3x³ - 10x² + 13x)  -  (5x³ + 4x² - 9x)

3x³ - 10x² + 13x  - 5x³ - 4x² + 9x  Change all terms after the subtraction sign to

                                                      the opposite sign (definition of Subtraction)

(3x³ - 5x³) + (-10x² - 4x²) + (13x + 9x)    Group like terms together

-2x³ - 14x² + 22x                                    

Answer:

480

we round up because the last number is bigger than 5