Answer is a, 57.49.
17.42-12.60-9.62= $-4.80+62.29=57.49
plane 1 travels 395 miles in 1 hour
plane 2 travels 422 miles in 1 hour
together, they travel (395+422) 817 miles in 1 hour
to have 2451 miles between then, they'd need to travel

so in 3 hours, they'll be 2451 miles apart
Congruent is the same size and same shape. When a ray bisects an angle, the two newly created angles will be congruent, since the ray went right in the middle of the first angle (so in this case, ABC and DBC will be congruent)
16 is the greatest common denominator