surface area
posted by lilman on .
Find the surface area of the cylinder in terms of pi.
I know the formula is SA=LA+2B, but not sure how to plug in the numbers and get answers. Everytime I try I get wrong answer.
The cylinder has I assume radius 8in and height 20in.
possible answers
352piin^2
320piin^2
832piin^2
448piin^2
It's possible I may have the numbers switched around. Can someone please help?

Visualize opening up a can (cylinder) and flattening out the pieces.
Don't you have 2 circles + a rectangle ?
The length of the rectangle would be the circumference of the circle, which is 16π
total area = 2circles + 1 rectangle
= 2(π(8^2)) + (16π)(20)
= 128π + 320π = 448π
(the formula you stated was useless to me since You did not define what L, A, and B stand for) 
Thank you I see where I messed up, it was on the second spot where you got 320.