Answer:
∠ 4 = 140°
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
∠ 4 is an exterior angle of the triangle, then
∠ 4 = ∠ 1 + ∠ 2 ( substitute values )
11x + 8 = 6x + 7 + 4x + 13
11x + 8 = 10x + 20 ( subtract 10x from both sides )
x + 8 = 20 ( subtract 8 from both sides )
x = 12
Then
∠ 4 = 11x + 8 = 11(12) + 8 = 132 + 8 = 140°
