1. Surface Areas of Spheres
Recognize and define the basic properties of speres.
Find surface areas of spheres.
Scenes such as reflective spheres over a checkerboard plane can be generated using computer ray-tracing.

2. PROPERTIES OF SPHERES
A segment with endpoints that are the center of the sphere and on the sphere is a radius of the sphere.
A chord of the sphere is a segment with endpoints that are on the sphere.
A chord that contains the center of the sphere is a diameter of the sphere.
A tangent to a sphere is a line that intersects the sphere in exactly one point.

3. PROPERTIES OF SPHERES
Hemisphere
Great Circle

4. Key Concept Surface Area of a Sphere
If a sphere has a surface area of T square units and a radius of r units, then
T = 4r2 r

5. Example 1 Surface Area
Find the surface area of the sphere given the area of the great circle.
A  in2

6. Example 2 Surface Area
Find the surface area of the hemisphere.
4.2 cm

7. Example 3 Surface Area
BASEBALL Find the surface area of a baseball with a circumference of 9 inches to determine how much leather is needed to cover the ball.