A tennis ball has a diameter of about 2.5 inches a can of three tennis balls is sold in a cylindrical can find the surface area of the can without the lid?

Answer 1

We'll allow the can to be both a tight fit and made of an incredibly thin material, and we'll use 2.5 as the diameter of the can also.
The area of the base of the can is calculated on the radius of the can, so we need to divide the diameter in two - this gives us 1.25"
As there is no lid we only need the area of the base, and the area of the side.

Base
The area of a circle is πr2 ........ r2 in this instance is 1.25 x 1.25 = 1.5625 and we'll used 3.1416 as π ...... that gives an area for the base of the can of 3.1416 * 1.5625 = 4.90875 square inches.

Side
The side of the can will be 3 times 2.5" tall as the balls sit one on the other.
The circumference of the side is that of the base = and is π times the diameter..... 3.1416 x 2.5 = 7.854 square inches.

Adding the base and the side we get 4.90875 + 7.854 = 12.76275 square inches.

CORRECTION

The Base calculation is OK, but the author erred in answering the Side.

The circumference is 3.1416 x 2.5 (pi times diameter) = 7.854 inches. The height is 3*2.5 = 7.5 inches. The area of the side is height x circumference = 7.854 x 7.5 = 58.905 sq inches.

Thus, the total is 4.909 + 58.905 = 63.814 sq inches.