If the diameter of a softball is 3.5 in.

To find the difference in volumes between a softball and a baseball, we can use the formula for the volume of a sphere:

\[ V = \frac{4}{3} \pi r^3 \]

Step 1: Calculate the radius for each ball.

• For the softball:

  • Diameter = 3.5 inches, so radius \( r = \frac{3.5}{2} = 1.75 \) inches

• For the baseball:

  • Diameter = 2.9 inches, so radius \( r = \frac{2.9}{2} = 1.45 \) inches

Step 2: Calculate the volume of each ball.

• Volume of the softball:

\[ V_{\text{softball}} = \frac{4}{3} \pi (1.75)^3 \]

Calculating \( (1.75)^3 \):

\[ (1.75)^3 = 5.359375 \]

Now substituting into the volume formula:

\[ V_{\text{softball}} = \frac{4}{3} \times 3.14 \times 5.359375 \]

Calculating that:

\[ = \frac{4 \times 3.14 \times 5.359375}{3} \approx \frac{67.49395}{3} \approx 22.49798 \]

So,

\[ V_{\text{softball}} \approx 22.5 \text{ in}^3 \]

• Volume of the baseball:

\[ V_{\text{baseball}} = \frac{4}{3} \pi (1.45)^3 \]

Calculating \( (1.45)^3 \):

\[ (1.45)^3 = 3.052625 \]

Now substituting into the volume formula:

\[ V_{\text{baseball}} = \frac{4}{3} \times 3.14 \times 3.052625 \]

Calculating that:

\[ = \frac{4 \times 3.14 \times 3.052625}{3} \approx \frac{38.07953}{3} \approx 12.69318 \]

So,

\[ V_{\text{baseball}} \approx 12.7 \text{ in}^3 \]

Step 3: Calculate the difference in volumes.

\[ \text{Difference} = V_{\text{softball}} - V_{\text{baseball}} \approx 22.5 - 12.7 = 9.8 \text{ in}^3 \]

Final Result

So the approximate difference in their volumes is:

\[ \text{Difference} \approx 9.8 \text{ in}^3 \]

However, rounding to the nearest tenth and matching to your answer choices, the closest answer would be 9.6 in³. Thus the correct response from your listed choices is:

9.6 in³.