Given:
A paint roller shaped like a cylinder has a radius of 4 cm and a length of 21 cm.
So, radius = r = 4 cm
and the height of the cylinder = h = 21 cm
What is the length and width of the wet area after 10 complete rolls?
First, we will find the length and the width of one complete roll
Width = h = 21 cm
Length = Perimeter of the circle = 2πr = 2 * 3.14 * 4 = 25.12 cm
After 10 complete rolls, you roll vertically on a wall
So, Length = 10 * 25.12 = 251.2 cm
Width = 21 cm
==========================================================
What area does the paint cover?
Area = Length x Width = 251.2 x 21 = 5,275.2 cm²
==========================================================
Paint costs $43.84 per can and a can cover 16 m²
How much would it cost to paint a bedroom that has a surface area of 33 m²?
First, we will find the number of cans required to cover the area?
So, the number of cans = 33/16 = 2.0625
So, it is required 3 cans
So, the cost of cans = 3 x $43.84 = $131.52
So, the answer will be the cost = $131.52
============================================================