15. suppose that pq bisects ∠mpn. what conclusion can you make?

The bisector of an angle is a ray that separates the angle  into two congruent angles.

As, PQ bisects

then,

By the definition of congruent angle : An angle that have the same measure

As you can also see in the figure as shown below;

add all the numbers and check the ones place.

the answer is 486. as the ones place is more than 4, the estimation will be the next 10 ie, 490