1. 12-4 Spheres

2. Sphere
3-dimensional shape with no bases. Circle rotated around it’s diameter. (Ball)
A = 4πr2 r
V = 4/3πr3 r r
Why no LA and TA?
There are no bases:
TA = LA + B

3. TOO Page 500 CLASSROOM Ex. #2 & 4 Answers: 2) A = 256π, V = (2048π)/3
4) r = 3, V = 36π

4. Example
Find the area of the circle formed when a plane passes 7cm from the center of a sphere with radius 8. (It’s the SONG!!!!)
72 + r2 = 82 r
r = √15 7 8
A = π(√15)2
A = 15π cm2

5. Example
A scoop of ice cream with diameter 6 is placed in an ice cream cone with diameter 5 and height 12. Is the cone big enough to hold all the ice cream if it melts?
What are we talking about?
Volume! 3 12
V of Sphere
36π
V of Cone
25π
>
2.5 NO

6. Homework
Page 500 #1-16, 19 (skip #9, 10, 15)