8.3 Video Lesson Notes:

Volumes of Spheres

Lesson Objective: Use a formula to find the volume of a sphere

* A sphere is the set of all points in space that are the same distance from a point called the center.  The radius (r) is the distance from the center to any point on the sphere.  A sphere does not have a base.

* Volume of a Sphere:

The volume V of a sphere is the product of (4/3)π and the cube of the radius of the sphere

                V = (4/3)πr3

Example 1: Find the volume of the sphere.  Round your answer to the nearest tenth.

Example 2: Find the radius of the sphere.  

Example 3: *A hemisphere is one-half of a sphere.  The top of the silo is a hemisphere with a radius of 12 feet.  What is the volume of the silo?  Round your answer to the nearest thousand.

8.3 Practice Problems

Find the volume V or radius r of the sphere.  Round your answer to the nearest tenth, if necessary.

1)                        2.)                                                                                  

3) Find the volume of the composite solid.  Round your answer to the nearest tenth.