Question

If the radius of a circle is increasing at the constant rate of 2cm/s find the rate of increase in its area, when it's radius is 20cm ?​

Answer 1

Explanation:

The radius of a spherical ball is increasing at a rate of 2 cm/min. At what rate is the surface area of the ball increasing when the radius is 8 cm? The surface area of a sphere with radius r is given by 4πr2. So, the rate at which the surface area is changing when r = 8 cm is 128 cm2/min.