An angle in a triangle measures 138 °. The other two angles are congruent. Enter and solve an equation to find the x measure of the congruent angles. An equation is _______ = 180. Angles congruent with each measure ________

Hey there! I"m happy to help!
The interior angles of a triangle add up to 180. We have 2 angles that have a value of x, so 2x+138=180.
We subtract 138 from both sides.
2x=42
We divide both sides by 2
x=21.
Have a wonderful day! :D