An open topped cylinder has a volume of 125 cubic inches. Express the surface area of the cylinder as a function of its radius.

1 answer

radius --- r
height --- h

V= πr^2 h
125/(πr^2) = h

SA , assume there is a bottom
SA = πr^2 +2πr h
= πr^2 = 2πr(125/(πr^2)
= πr^2 + 250/r