Equations for Missing Angles

Find the missing angle.  Find x.

• 20^o

• 70^o

• 160^o

• 180^o

The angles are adjacent supplementary angles. Find the value of x.

• 42 

• 180 

• 126 

• 60

Set up the equation to find the missing angle

• 40 + 90 = x

• 40 + 90 + x = 180

• 180 = 40 - 90

• x + 40 + 40 = 180

• 34x +28 = 180

• 34x = 10

• 12x + 19 = 22x - 9

• 12x + 19 + 22x - 9 = 180

Set up an equation that will help you solve for x.

• 60 + 75 + 180 = x

• 60 + 75 + x = 180

• 60 + 75 = x

• 60 + x = 75

Set up the equation to solve for x

• 8x + 2 +70 + 60 = 180

• 8x + 2 = 180

• 8x + 2 = 70 + 60

• 70 + 8x + 2 = 60

Set up the equation to solve for the missing angle

• 50 + 120 + x = 180

• x + 50 = 120

• 120 + 50 = x

• x + 120 = 50

Set up an equation to find the missing angle

• 50 + 115 = x

• x + 50 + 115 = 180

• x + 50 = 115

• 50 + x = 180

Set up an equation that will help you find the missing angle

• 58 + x = 28

• x + 28 = 58

• 28 + 58 + x = 180

• 28 + 58 = x

Set up an equation that will help you solve for x

• x + 21 = 34

• 21 + 34 + x = 180

• 21 + 34 = x

• 34 + x = 21