Question

by decreasing each dimension by 1 unit, the area of a rectangle decreased from 20 square feet (on the left) to 12 square feet (on the right). find the percent decrease in area. the percent decrease in area is (%).

Explanation:

Step1: Recall percent - decrease formula

Percent decrease=$\frac{\text{Original value}-\text{New value}}{\text{Original value}}\times100\%$

Step2: Identify original and new values

The original area of the rectangle is $A_1 = 20$ square feet and the new area is $A_2=12$ square feet.

Step3: Calculate percent - decrease

Percent decrease=$\frac{20 - 12}{20}\times100\%=\frac{8}{20}\times100\% = 40\%$

Answer:

40