13.1 VOLUME OF SPHERES

13.1 VOLUME OF SPHERES BY: BRADLEY BINDER AND DAKOTA HARRISON

OBJECTIVES • Find the volume of spheres and hemispheres

definitions • Sphere- in a space the set of all points that are a given distance from a given point called the center (p. 638) • Hemisphere- one of the two congruent parts into which a great circle separates a sphere (p. 672)

Formulas • Volume of a Sphere • 4/3 (πr3) • Hemisphere • 2/3 (πr3)

Example 1 Find the volume of the sphere if the radius is 18.

Example 1 cont’d • 4/3 (πr3) Given • 4/3 (183π) Substitution • 4/3 (5,832 π ) Multiplication • 4/3(18,321.8) Multiplication • Answer: 24,429 units3

Example 2 Find the volume of the hemisphere if the radius is 9.6 meters.

Example 2 cont’d • 2/3 (πr3) Given • 2/3 (9.63π) Substitution • 2/3 (884.7π) Multiplication • 2/3 (2,779.4) Multiplication • Answer: 1,852.9 meters3

Example 3 Find the volume of the sphere if the circumference is 36.

Example 3 cont’d • C=2 π r Given • 36=2 π r Substitution • 36/(2π) =r Division • r = 5.7 units

Example 3 still Cont’d • 4/3 (πr3) Given • 4/3 (5.73π) Substitution • 4/3 (185.2 π ) Multiplication • 4/3 (581.8) Multiplication • Answer 775.7 units3

Assignment • Pages 704-705 • Problems 9-20, 30&31

13.1 VOLUME OF SPHERES