Question

Angle a and b are supplementary angles. If m a = (x – 40)0 and m b = (x + 20)0, find the value of x, m a and m b

Answer 1

∠ a = 60° , ∠ b = 120°

Explanation:

Supplementary angles sum to 180° then

x - 40 + x + 20 = 180 , that is

2x - 20 = 180 ( add 20 to both sides )

2x = 200 ( divide both sides by 2 )

x = 100

Then

∠ a = x - 40 = 100 - 40 = 60°

∠ b = x + 20 = 100 + 20 = 120°

Answer 2

x=100 a=60 b=120

Explanation:

Supplementary angles add 180 degrees

(x-40) + (x+20) = 180

2x-20 =180

2x =100

x = 100

100-40 = 60

100+20 = 120

60+120 +180