How do i solve these? did i get the first one wrong?

For the first one:

s = 2*pi*r*h

Solve for r like this:

s = 2*pi*r*h

r = s/2*pi*h , that is the last answer that is given as a choice, and it's correct.

For the second one:

c = 8*pi*a*b

Solve for a like this:

c = 8*pi*a*b

a = c/8*pi*b, that is the first answer that is given as a choice, and it's correct.

Basically, you need to divide both sides with everything that is next to the variable you are asked to be solved with.

Hope this helps!

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.

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step-by-step explanation:

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