a plane takes off at 10.00am from an airfield, and flies at 120km/h on a bearing of N35W. A second plane takes off at 10.05am from the same airfield, and flies on a bearing of S80E at a speed of 90km/h. How far apart are the planes at 10.25am?

Answer 1

Did you make a sketch?
At the time of our calculation ,
the first plane flew for 25 min or 5/12 hr
the 2nd plance flew for 20 min or 1/3 hr

distance covered by 1st plane = (5/12)(120) = 50 km
distance covered by 2nd plane = (1/3)(90) = 30 km
I found the angle between them to be 135°

looks like a standard cosine law question....

x^2 = 50^2 + 30^2 - 2(50)(30)cos135°
= .....

careful, the cos135° is negative , making that last term positive.

Answer 2

A plane flies in a direction of N70°E for 80 km and then on a bearing of S10°W for 150 km.
a How far is the plane from its starting point?
b What direction is the plane from its starting point?