Answer:
m∠a = 107°
Step-by-step explanation:
According to the Alternate Exterior Angles Theorem, when two parallel lines are intersected by a transversal, the angles that are exterior to the parallel lines and on the alternate sides of the transversal are congruent.
In this case, ∠a and the angle measuring 107° are exterior to the parallel lines and on alternate sides of the transversal, which means they are congruent, so:
[tex]\Large\text{$\sf m \angle a=\boxed{\sf 107}^{\circ}$}[/tex]
