Question

The side of a square decreases from 21cm to 7cm. What is the percentage decreases in its area?​

Answer 1

Step-by-step explanation:

Let the side of the given square be x, then its area is x^2.

When the side is decreased by 20%, new side is x(100–20)/100=x*80/100=0.8x

Area of the new square=(0.8x)^2= 0.64x^2

Difference in areas is =x^2–0.64x^2=0.36x^2

Percentage decrease =(0.36x^2/x^2)*100=0.36*100=36%

Answer 2

Answers

the area that decrease is 36%