Answer:
The sum of the interior angles in a triangle is 180°. Therefore, we have:
A + B + C = 180
Substituting in the given values, we get:
87° + 39° + (5x + 2)° = 180°
Simplifying and solving for x, we get:
131° + 5x = 180°
5x = 49°
x = 9.8°
Therefore, the measure of angle C is:
5x + 2 = 5(9.8°) + 2 = 49° + 2 = 51°
So, the answer is (C) 51°.
Explanation: