Explanation:

- The formula for the volume of a sphere is \( V = \frac{4}{3} \pi r^3 \).

- A 10% decrease in the radius means the new radius is \( 0.9r \).

- Substituting the new radius into the volume formula gives \( V_{\text{new}} = \frac{4}{3} \pi (0.9r)^3 = \frac{4}{3} \pi \times 0.729r^3 \).

- The decrease in volume is therefore \( 1 - 0.729 = 0.271 \) or 27.1%.

- Calculating this shows the percent decrease in volume:

- 1. The original formula is reduced to 72.9%.

- 2. The result is a 27.1% decrease in volume.

- Therefore, the volume decreases by 27.1%.

?? The correct answer is Option 2: 27.1%