Let each one of the two congruent angles have measure x.
The third angle's measure is x + x - 36
We know that the sum of the measures of the angles of a triangle equals 180 deg.
We add the measures of the three angles, and we set the sum equal to 180.
Then we solve for x.
x + x + x + x - 36 = 180
4x - 36 = 180
4x = 216
x = 54
The two congruent angles measure x, so their measure is 54.
The measure of the third angle is x + x - 36 = 54 + 54 - 36 = 72
The measures of the three angles are 54 deg, 54 deg, 72 deg.
