Question

John builds a cylinder with a radius of 7 inches and height of 10 inches. Jeff builds a cylinder with a radius of 6 inches and height of 8 inches. How much more material does John use?

Answer 1

`257.74 in^2`

Explanation:

Step one:

Given data

John's cylinder

radius of 7 inches and

height of 10 inches

Required:

The difference in the total surface areas of the two cylinders

`A=2 \pi rh+2 \pi r^2`

substitute we have

`A=2 *3.142* 7*10+2 *3.142*7^2\\\\A=477.68+307.916\\\\A=785.596 in^2`

Jeff's cylinder

radius of 6 inches and

height of 8 inches

`A=2 *3.142* 6*8+2 *3.142*6^2\\\\A=301.632+226.224\\\\A=527.856 in^2`

The difference in the total surface areas is

=785.596-527.856

=257.74 in^2