10.8: The Power Theorems

1. 10.8: The Power Theorems

2. Chord-Chord Power Theorem • Used when two chords intersect. • Multiply both parts of the chord together. Then set them equal. W I (WY) (YN) = (IY) (YD) Y N D

3. Secant-Tangent Power Theorem • Used when a secant and tangent intersect. • Multiply the secant by its external piece and set it equal to the square of the tangent. C (RO) (RC) = (RE)2 O R E

4. Secant-Secant Power Theorem • Used when two secants intersect • Multiply one secant by its external part and set equal to the outside of the other secant multiplies by itself. (SI) (VS) = (ST) (SA) V I S T A

5. Example 1 Given: PA = 5, SP = 7, AC = 4 Find: AE S P A C E

6. Example 2 Given: DE = 11, ID = 3, VI = 4 Find: IR R D I V E

7. Example 3 Given: UA = 3, DU = 9 Find: AL D U A L

8. Example 4 Given: PO = 4, OK = 16, O is the mdpt. of Find: SO P S E O K

9. Example 5 Given: TE = 4, TL = 10, TN = 5 Find: IN I N T E L

10. Homework p. 495 1-5, 9-11, 16