Answer:
∠ = 130°
Explanation:
They are vertical angles: a pair of opposite angles formed by intersecting lines. These two angles are considered congruent, which means they have exactly the same measure. So, you simply solve for x when they equal each other. Remember, both angles share the same measurement.
15x -5 = 13x + 13
5 + 15x - 5 = 13x + 13 + 5
13x - 15x = 13x + 18 - 13x
2 ÷ 2x = 18 ÷ 2
x = 9
Now you must put 9 in for x to solve the measurement of the angles.
15 (9) - 5 = 130°
13(9) + 13 = 130°
Both angles equal 130°, so you know you've done the math correctly.