Paint Roller A has a length of 12 in. and a diameter of 2 in. Paint Roller B has a length of 8 in. and a diameter of 3 in. Which roller can spread more paint on a wall in one revolution

3 answers

Use the formula:

A = 2 * pi * r * h
a= 2 x 3.14x 1 x 12
a = 75.36

a = 2 x 3.14x 8 x 3

a= 150.71

roller B
In b, you used the diameter, not the radius.

2 * 3.14 * 1.5 * 8 = 75.36

They both cover the same amount of wall in one revolution.