1. Objectives: SWBAT examine relationships between pairs of angles SWBAT find missing angle measures when given a visual image of angles SWBAT utilize algebra to find missing angle measures

2. Use Algebra to Find Missing Angle Measures ALGEBRA Angles DEF and WXY are complementary angles, with m  DEF = 2x and m  WXY = 3x – 20. Find the measures of  DEF and  WXY. m  DEF + m  WXY = 90Complementary angles 2x + 3x – 20 = 90Replace m  DEF with 2x and m  WXY with 3x – 20. Step 1 Find the value of x.

3. Use Algebra to Find Missing Angle Measures Combine like terms. Add 20 to each side. Simplify. Divide each side by 5. Simplify.

4. Use Algebra to Find Missing Angle Measures Answer: m  DEF = 44° and m  WXY = 46° Step 2 Replace x with 22 to find the measure of each angle. m  DEF = 2xm  WXY = 3x – 20 = 2(22) or 44 = 3(22) – 20 or 46

5. ALGEBRA The measure of  D = 5x – 5.9 and the measure of  E = x + 61.1. If the angles are supplementary, find the value of x and m  E.

6. A.A B.B C.C D.D A.m  ABC = 12° and m  RST = 78° B.m  ABC = 20° and m  RST = 70° C.m  ABC = 30° and m  RST = 60° D.m  ABC = 30° andm  RST = 70° Angles RST and ABC are complementary angles with m  RST = 3x and m  ABC = x + 10. What are the measures of  ABC and  RST?