Students need to substitute the value of the radius in the formula V = 4/3 πr^3 to find the volume of the sphere. For example, Ammi bought a snow globe during a recent vacation to New York City. The globe is a hemisphere with a diameter of 3 inches.

If the radius of a sphere is 3 in, then the formula V = 4/3 πr^3 becomes V= 4/3π(3)^3. After simplifications, the final value can be V=36π cubic inches. The volume of the hemisphere is half of the volume of sphere, therefore the volume of Ammi’s snow globe is 18π cubic inches.