the diameter of a cylinder is one half the height. Express the total surface area as a function of the height h.

Question

Can someone please help me with this question

Answer 1

D = h/2

Total surface area:
A = pi D h + 2 pi D^2
= pi D(h + 2 D)

Now substitute h/2 for D in that equation.

A = pi h/2 (2 h)
= pi h^2