Question

Solve for the missing angle below

Answer 1

x=21, 5x=105, 3x+12=75

Explanation:

5x+(3x+12)=180

8x + 12 =180

8x = 168

x=21

5x=21*5=105

3x+12=3*21+12=63+12=75

Answer 2

x = 21

5 x = 105

3 x + 12 = 75

Explanation:

Angles on a straight line add to 180° so

5 x + 3 x + 12 = 180

Add the x's together

8 x + 12 = 180

Minus 12 from both sides

8 x = 168

Divide both sides by 8

x = 21

Now we can substitute x into 5 x and 3 x + 12

5 x = 5 × 21 = 105

3 x + 12 = 3 × 21 + 12 = 63 + 12 = 75