Answer:
x=72 and the exterior angle is 154
Step-by-step explanation:
We will call the unknown angle in the triangle y. Angle y and the angle (2x +10) form a straight line so they make 180 degrees.
y + 2x+10 =180
Solve for y by subtracting 2x+10 from each side.
y + 2x+10 - (2x+10) =180 - (2x+10)
y = 180-2x-10
y = 170-2x
The three angles of a triangle add to 180 degrees
x+ y+ 82 = 180
x+ (170-2x)+82 = 180
Combine like terms
-x +252=180
Subtract 252 from each side
-x+252-252 = 180-252
-x = -72
Multiply each side by -1
-1*-x = -72*-1
x=72
The exterior angle is 2x+10. Substitute x=72 into the equation.
2(72)+10
144+10
154
