Question

A cylinder of base diameter 8cm and height 7cm is dipped vertically one third in a bucket full of paint. How much area gets painted?

Answer 1

Here, you need to solve for the bottom 1/3 of the surface area of the cylinder.

This would include:

• the bottom of the cylinder Area = πr²

= (4cm)²π

= (16cm²)π

• and 1/3 area of the side, which is a rectangular piece = 1/3 height x circumference

= (1/3)(7cm)(8cm)π

= (18.67cm²)π

• Add these together to get the bottom 1/3 of the cylinder

SA = (16cm²)π + (18.67cm²)π

SA = (34.67cm²)π

SA = 108.91cm²