Asked by kelvin

please guys help me this question, how to solve it.

Calculate the total surface area of a hollow cylinder whose radius is 15 cm and height is 20 cm.

What formula can be applied between
(a) SA = 2pie*r*h + 2pie*r^2
(b)SA = 2pie*r*h
State the reason why you choose (a) or (b).
Answered by Steve
not (a) since the ends are not included
not (b) since there is an inside and an outside

and it's <u>pi</u> not "pie"
Answered by Henry
As = 2*(pi*r^2) + 2pi*r*h.
My choice is "a" , because it includes the area of the circular ends and the
area due to the ht. of the cylinder.