Solve A= 2pirsq+2pirh

Question

I can't for the life of me figure out this problem! Solve A equals 2 pi R squared plus 2pi r h solving for pi

Answer 1

It looks like you were given the formula for the surface area of a cylinder of radius r and height h.  Each end-face has an area of πr².  The rest of the surface area is the product of circumference and height, (2πr)h.  Then total surface area is

 

A = 2πr² + 2πrh = 2πr(r + h)

 

If they want you to get π from A, knowing r, then

 

π = A / [2r(r + h)]

 

What I find unusual about this problem is that they ask you to find π rater than to use π to calculate circumference, area, or volume.

Answer 2

A=2∏r^2+2∏rh

factor out ∏

A=∏(2r^2+2rh)

A/(2r^2+2rh)=∏