**Example**

The volume of the sphere pictured on the left is:

$$ v = \frac{4}{3} \pi r^3 \\ v = \frac{4}{3} \pi \cdot 3^3 \\ v = 36 \pi \\ = 113.1 \\ $$

**Practice** Problems

##### Problem 1

$$ v = \frac{4}{3} \pi r^3 \\ v = \frac{4}{3} \pi \cdot 7^3 \\ = 457.3 \text{ cubic inches} \\ $$

##### Problem 2

First, remember that we need to divide the diameter by 2 to get the radius of 5 for our formula:

$$ v = \frac{4}{3} \pi r^3 \\ v = \frac{4}{3} \pi \cdot 5^3 \\ v = 36 \pi \\ = 523.6 \text{ cubic inches} \\ $$