Spheres

1
Spheres

• Lesson 12.4
• Pre-AP Geometry

2
Lesson Focus

• Spheres are common figures in the real world.
• In this lesson, the formulas for calculating the
  surface area and volume of a sphere are used to
  solve problems.

3
Theorem 12-9

• The area of a sphere equals 4p times the square
  of the radius.

4
Surface Area of a Sphere
Area 4pr2
5
Theorem 12-10

• The volume of a sphere equals 4p/3 times the
  cube of the radius.

6
Volume of a Sphere
7
Circle of Intersection

• The intersection of a sphere and a plane is
  either a tangent point or a circle called the
  circle of intersection.

8
Practice

1. Determine the surface area and volume of a sphere
   with diameter 12. (Leave the answer in terms of
   p.)
2. Determine the surface area and volume of a sphere
   with radius 2r. (Leave the answer in terms of p.)

9
Written Exercises

• Problem Set 12.4A, p.500 2 - 16 (even)

10
Written Exercises

• Problem Set 12.4B, Handout 12-4