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Mathematics 7 Online
OpenStudy (anonymous):

Write an expression for the volume of a cylinder with a height 7in. greater than the radius.

OpenStudy (anonymous):

First look up the formula for volume of a cylinder.

OpenStudy (anonymous):

V = pi*r^2*h

OpenStudy (anonymous):

The height is 7 in greater than the radius. How would you write that expression?

OpenStudy (anonymous):

x + 7

OpenStudy (anonymous):

So put that in to your equation.

OpenStudy (anonymous):

pi*r^2*(x + 7)

OpenStudy (anonymous):

Be sure to be consistent with your variables. The height is in relation to the length of the radius.

OpenStudy (anonymous):

so change the x to a r?

OpenStudy (anonymous):

That is what I would do. It really doesn't matter which one you use as long as you are consistent.

OpenStudy (anonymous):

so it would read pi*r^2*(r + 7)

OpenStudy (anonymous):

Yes, but you probably need to simplify.

OpenStudy (anonymous):

how?

OpenStudy (anonymous):

Distribute.

OpenStudy (anonymous):

how

OpenStudy (anonymous):

Multiply the term outside the parenthesis by each of the terms inside the parenthesis.

OpenStudy (anonymous):

pi*r^3+7r^2?

OpenStudy (anonymous):

Exactly.

OpenStudy (anonymous):

thanks alot!

OpenStudy (anonymous):

Your welcome.

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