2. A tennis player has 6 balls with a diameter of $6 \mathrm{~cm}$. Find the volume of all 6 balls.
Volume of all 6 Tennis Balls = $\pi \mathrm{cm}^{3}$

Step 1 ：The problem provides the diameter of the tennis balls as 6 cm. The radius of the balls is half the diameter, so the radius is 3 cm.

Step 2 ：The volume of a sphere can be calculated using the formula \(\frac{4}{3} \pi r^{3}\), where r is the radius of the sphere.

Step 3 ：Substituting the radius into the formula, the volume of one ball is \(\frac{4}{3} \pi (3)^{3} = 113.09733552923254 \, \text{cm}^{3}\).

Step 4 ：There are 6 tennis balls, so the total volume is \(6 \times 113.09733552923254 = 678.5840131753953 \, \text{cm}^{3}\).

Step 5 ：Final Answer: The volume of all 6 tennis balls is \(\boxed{678.58 \, \text{cm}^{3}}\).