A triangle has an exterior angle with a measure of 120°. Can you determine the measures of the interior angles? Explain.

If the exterior angle is 120 degrees, you subtract 120 degrees from 360 degrees (the two angles form a circle) and get 240 degrees.

This is not a possible angle for a triangle because the angles in a triangle always add up to 180 degrees. Also, angles in triangles can’t be more than 180 degrees