1. Section 12-4 Spheres

2. Recall… Set of all points in space at a given distance from a given point. Sphere:

3. Great circle The intersection of a plane and a sphere so that the center of a sphere is included

4. hemisphere Two congruent halves of a sphere separated by a great circle.

6. Theorem 12-9 The area of a sphere equals times the square of the radius.

7. Theorem 12-10 The volume of a sphere equals times the cube of the radius.

8. True or False 1.Every plane that intersects a sphere is a great circle. 2.The Eastern Hemisphere of Earth is congruent to the Western Hemisphere of Earth. True False

9. True or False 3.The diameter of a sphere is congruent to the diameter of its great circle. True