3.) 20 + 130 + ? = 180
150 + ? = 180
? = 30°
5. A straight line is 180°, so you could do 137 + x = 180 to find the angle of the top of the triangle. x = 43°
Next find the last missing angle of the triangle. 102 + 43 + x = 180
x = 35°
To find ? you do: 35 + ? = 180
? = 145°
6. ? = 135° (use the steps above and try to find the missing angles of the triangle to help you find ?)
7. ? = 130°
8. ? = 85 °
