Hi! I need help with the following math problem:

A building has 4 columns, each of which is 15 ft high and has a circumference of 1 2/3 yards.
1. Find the lateral surface area of the 4 columns.
2. How much will it cost to paint the 4 columns if paint costs $1.10 a square yard?

If anyone could explain both parts of the problem step by step to me, that would be great! Thanks.

1 answer

From the circumference of the columns, compute the radius R. Use feet instead of yards.

R = 5 ft/(2 pi) = 0.7958 feet

The lateral surface area of each column is 2 pi R H = 75 sq. ft.

Actually, we did not have to compute R, because the lateral surface area = (circumference) x (height) = 5 x 15

Since there are 4 coulumns, 300 square feet must be painted. Divide that by 9 fr square yards: 33.33 sq. yd

Muyltiply that by $1.10/sq.yd for the final answer in dollars.