Answer: 96°
Step-by-step explanation:
If a triangle is being drawn, Angle A and C will be the two remote interior angles in the triangle. The sum of the two interior angles has to equal to the exterior angle.
Set them equal each other and solve for x.
(3x-6) + (6x +12) = 12x - 24 Combine like terms
9x + 6 = 12x - 24 Subtract 6 from both sides
- 6 -6
9x = 12x - 30 Subtract 12x from both sides
-12x -12x
-3x = -30 Divide both sides by -3
x = 10
Now since x is 10 degrees we will need to input the value into in for x in the exterior angle expression and break it down.
Exterior : 12(10) - 24
120 - 24 = 96
This means the measure of the exterior angle at vertex B is 96 degrees.
