# Related Rates Question

1. Nov 30, 2007

### CalXeon

A plane flying with a constant speed of 4 km/min passes over a ground radar station at an altitude of 14 km and climbs at an angle of 40 degrees. At what rate, in km/min is the distance from the plane to the radar station increasing 3 minutes later?

The only equation I am using is the cosine law:
c^2=a^2+b^2-2abCos(Angle)

a=14
b=(i am not sure if its 4 or not)

I have been doing this:
c^2= 14^2+ b^2- 2(14)b cos(130)

$$a^2 + b^2 = c^2$$.