CPM Homework Banner

Home > A2C > Chapter 4 > Lesson 4.2.1 > Problem 4-70

4-70.
  1. Lilia wants to have a circular pool put in her backyard. She wants the rest of the yard to be paved with concrete. Homework Help ✎

    1. If her yard is a 50 ft. by 30 ft. rectangle, what is the largest radius pool that can fit in her yard?

    2. If the concrete is to be 8 inches thick, and costs $2.39 per cubic foot, what is the cost of putting in the concrete? No concrete will be used in the pool. (Reminder: Volume = (Base Area · Depth ).

Draw the rectangle.

Fit the largest possible circle into the rectangle (it does not have to be in the center).

The radius of the pool is 15 ft.

Find the area of the yard (rectangle) and the area of the pool (circle).

Subtract the area of the pool from the area of the yard to find the area that will be paved.

A = 1500 − 225π ≈ 793.14 ft.2

Now multiply by the price per cubic foot to find the total cost.

The total cost is $1,263.74.