The radius of a spherical soap bubble is increasing at the rate of 0.2 cm/sec. Find the rate of increase of its surface area, when the radius is 7 cm.

Explanation

To solve the problem, we need to find the rate of increase of the surface area of a spherical soap bubble when the radius is 7 cm, given that the radius is increasing at a rate of 0.2 cm/sec.

### Step-by-Step Solution:

1. **Understand the formulas involved**:
- The formula for the surface area \( S \) of a sphere is given by:
\[
S = 4\pi r^2
...