The figure is not drawn to scale. PQ and MN are straight lines. Find

Answer:
a = 138
Step-by-step explanation:
Notice that from the figure, we can see that ∠MOQ and ∠PON are vertical angles, which means that by definition, they're congruent in measure.
∠MOQ = ∠MOR + ∠ROQ = 90 + 48 = 138°
So, this means that ∠PON is also equal to 138, which means a = 138.
Thus, the answer is a = 138.
~ an aesthetics lover