Answer:
x = 45
Step-by-step explanation:
The 2 interior angles of the triangle adjacent to both 3x's is
180 - 3x
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
2x is an exterior angle of the triangle, thus
180 - 3x + 180 - 3x = 2x , that is
360 - 6x = 2x ( add 6x to both sides )
360 = 8x ( divide both sides by 8 )
45 = x
