Math
posted by kaitlyn .
An aluminum cylindrical juice can has a height of 4 in. and a radius of 6 in. How many square inches of aluminum are needed to make the can?

For a can with both ends closed, Area reqd. = 2¡Çrh + 2¡Çr^2 where r=6,h=4 and assume ¡Ç=22/7, A=2640/7 sq in.
If one end of the can is open then A=2¡Çrh + ¡Çr^2 = 264 sq in. 
Area of circle = πr^2
Multiply by 2 to get top and bottom.
Circumference = 2πr
Area of side = 4 *2πr
Combine the data. 
376.8 in.2