Answer:
53.2 mph
Step-by-step explanation:
Mara's family travels 239.4 miles between the hours of 9:10 a.m. to 1:40 p.m.
1:40 p.m. is 13:40.
Thus, they traveled for
13 hours 40 minutes - 9 hours 10 minutes = 4 hours 30 minutes
that is 
hours.
Use formula:
where
D = distance
r = rate
t = time.
In your case,
D = 239.4 miles
t = 4.5 hours
Hence,
The arc length (s) is given in terms of the radius (r) and central angle (θ) by
s = r*θ . . . . . . . where θ is in radians
For your arc, the length is
s = (15 ft)*(π/4) ≈ 11.78 ft
_____
45° can be converted to radians by multiplying by π/180°.
45° * (π/180°) = π*(45/180) = π/4 . . . . radians
(16/18)
(24/27)
You just times 8 and 9 by the same number, like:
(8•2/9•2)=(16/18)
(8•3/9•3)=(24/27)
You could do any number:
(8•100/9•100)=(800/900)
