Question

by decreasing each dimension by 2 units, the area of a rectangle decreased from 40 square feet (on the left) to 18 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 $A_1 = 40$ square feet and the new area is $A_2=18$ square feet.

Step3: Substitute values into formula

Percent decrease = $\frac{40 - 18}{40}\times100\%=\frac{22}{40}\times100\%$.

Step4: Calculate the result

$\frac{22}{40}\times100\% = 0.55\times100\%=55\%$

Answer:

$55$