SOLUTION: Hi, Can you tell me how to find the surface area of a cylinder for this a=4 cm, b=7 cm? Thanks.

Algebra ->  Surface-area -> SOLUTION: Hi, Can you tell me how to find the surface area of a cylinder for this a=4 cm, b=7 cm? Thanks.       Log On


   

Question 103282: Hi, Can you tell me how to find the surface area of a cylinder for this
a=4 cm, b=7 cm? Thanks.
Answer by HyperBrain(694) About Me  (Show Source):
You can put this solution on YOUR website!
A good example is a can. Take note that it has TWO CIRCULAR bases. Something else happens when you 'unwrap' the can. It will make you a RECTANGLE with a length equal to the CIRCUMFERENCE of one base and a WIDTH equal to the HEIGHT of the cylinder.
Thus,
surface area =area of two bases + the area of the rectangle
area of the two bases=2%2Api%2Ar%5E2
area of the rectangle=%282%2Api%2Ar%29%2Ah
where r=radius
h=height
Thus,
surface area=2%2Api%2Ar%5E2+%282%2Api%2Ar%29%2Ah
Substituting r=4 and h=7,
S.A.=2%2Api%2A4%5E2+%282%2Api%2A4%29%2A7
=88%2Api