11-6 Surface Areas and Volumes of Spheres

Objective

To find the surface area and volume of a sphere

Image Long Description

In the Solve It, you considered the sizes of objects with circular cross sections.

A sphere is the set of all points in space equidistant from a given point called the center. A radius is a segment that has one endpoint at the center and the other endpoint on the sphere. A diameter is a segment passing through the center with endpoints on the sphere.

Essential Understanding You can find the surface area and the volume of a sphere when you know its radius.

Image Long Description

A baseball can model a sphere. To approximate its surface area, you can take apart its covering. Each of the two pieces suggests a pair of circles with radius r, which is approximately the radius of the ball. The area of the four circles, 4 π r 2 , 4 pi , r squared , comma  suggests the surface area of the ball.

Table of Contents