Question

Calculating the Measures of Interior Angles of a Triangle

Use the diagram showing m || n, as well as the relationships between interior and exterior angles of ΔABC, to answer the questions.

The measure of angle ABC is _ °.
The measure of angle BAC is _ °.
The measure of angle ACB is _°.

Answer 1

So its 60, 50, and 70 in that order...

Answer 2

Angle B is the linear pairs with 60°, so the size is 180-60=120°

Angle ABC is the linear pair with 120°, so the size is 180-120-60°

Angle A corresponds to angle 60°, so they are equal

Angle BAC is the linear pair with angle A and angle 70°, so 180-(60+70)=50°

Angle ACB is 180-(50+60) = 70°