Question

An exterior angle of a triangle is 140 degrees. If the non-adjacent angles are congruent, then what are the measures of all of the interior angles of the triangle?
60 degrees, 60 degrees, 60 degrees

70 degrees, 70 degrees, 40 degrees

60 degrees, 60 degrees, 40 degrees

100 degrees, 40 degrees, 40 degrees

Answer 1

Short Answer B
Remark
The non adjacent angles add up to the given exterior angle.

Equation
The two non adjacent angles are equal and add up to the exterior angle.
Let one of the non adjacent interior angles = x
x + x = 140
2x = 140     Divide by 2
x = 140/2
x = 70

Comment
So the next step is to find the third angle
70 + 70 + x = 180 Combine like terms.
140 + x = 180        Subtract 140 from both sides.
x = 180 - 140
x = 40

Conclusion
The angles = 40 + 70 + 70 

Answer
B <<<<