Question

If the lines a and b in the diagram below are parallelm why do angles 2 and 6 measure 60 degree angles

Because they are alternate interior angles.
Because they are corresponding angles.
Because they are alternate exterior angles.
Because they are same-side interior angles.

Answer 1

Angles 2 and 6 are corresponding angles, which would explain why they are congruent if lines a and b are parallel, but there is nothing in the problem to explain that any of the angles equals 60 degrees since no measurements were given in the diagram.