The document provides 3 examples of using the Law of Cosines to find the measure of an angle given the lengths of 3 sides of a triangle. The first example finds the measure of an acute angle C in a triangle with sides of lengths 5, 12, and 9. The second finds the right angle C in a triangle with sides of lengths 5, 12, and 13. The third finds the measure of an obtuse angle C in a triangle with sides of lengths 5, 12, and 15.

1. Homework 11­6: p. 810 p.787
1) 45
225
3) 13.7
5) 10.0 cm

2. Lsn 11­7: The Law of Cosines to find an angle measure.
Given three sides a, b, c, find the measure of <C.
1. Acute Angle
C
5 12
9

3. 2. Right Angle
C
12
5
13
3. Obtuse Angle
C
12
5
15