Question

on decreasing the radius of a circle by 30 percent its area is decreased by​

Answer 1

Answer:

We know that the radius of a circle decreased by 30%, we need to find the percentage decrease in its area. Area of a circle with radius r = πr2.

Now if the radius decreases by 30%, radius becomes r − (30% of r) = r − 0.3r = 0.7r, which changes the area of circle to π(0.7r)2=(0.49)πr2.

Using the formula: Percentage change =final−initialinitial×100, the percentage change in the area of the circle is (0.49)πr2−πr2πr2×100 = −51%, i.e. the new area is 51% less than the original area.