The number of bushes that is approximately needed for Mrs. Chase's backyard is 23 bushes
How many bushes are needed?
The number of bushes needed = perimeter of the backyard / 3 feet
The perimeter of the backyard is the sum of the three sides of the right triangle that is the shape of the backyard. The length of the third side would be detemined using Phythagors theorem.
Length of the third side : √30² - 12² = 27.50 feet
Perimeter of the backyard = 27.50 + 12 + 30 = 69.50 feet
The number of bushes needed =69.50 / 3 = 23.17 = 23 bushes
To learn more about triangles, please check: https://brainly.com/question/22949981