Answer:
183.27miles
Explanation:
Note that we are considering two planes.
Plane 1
Speed = 140 mph
Time = 2.5 hours
Distance = ?
Speed = distance/time
140 mph = distance/2.5hrs
Distance = 140×2.5
= 350miles
Plane 2
Speed = 170 mph
Time = 2.5 hours
Distance = ?
Speed = distance/time
170 mph = distance/2.5hrs
Distance = 170×2.5
= 425miles
The angle between side is 25 degree
From cosine rule
c^2 = a^2 + b^2 − 2abcos(tetha)
Where a = 350
b = 425miles
c^2 = 350^2+425^2-2(350×425)(cos25)
c^2 = 122500+180625-297500(0.906)
c^2 = 303125-269535
c^2 = 33590
C = √33590
C = 183.27miles
The distance they flew apart after 2.5hrs is 183.27miles