Answer:
Equation to solve is x+x+120=180
Solution to equation: x=30
Explanation:
The angles in a triangle have a sum 180 degrees.
You know one angle is 120 degrees.
If you assume another angle has a measurement of x degrees, then the remaining angle has a measurement of x degrees. We know this because congruent means they will have the same measurement.
So we have this equation to solve:
x+x+120=180
Combine like terms:
2x+120=180
Subtract 120 on both sides:
2x=180-120
Simplify:
2x=60
Divide both sides by 2:
x=60/2
Simplify:
x=30