Two angles are supplementary. The larger angle measures 120 degrees more than the smaller. What is the degree measure of each angle?

1 Answer
May 3, 2018

The first angle is 30 degrees. The second angle is 150 degrees. Here's why:

Explanation:

The first angle will be expressed as #x#. Since the second angle is #120# degrees greater than the first, it will be expressed as #(x + 120)#. Because they're supplementary, they'll add up to #180#:

#x + (x + 120) = 180#

Combine like terms.

#2x + 120 = 180#

Subtract 120 from both sides.

#2x = 60#

Divide by 2 to isolate for #x#.

#x = 30#

Plug your data back in:

30 + (30 + 120) = 180

First angle: 30 degrees
Second angle: 150 degrees