Question

An airplane leaves an airport and flies due west 120 miles and then 150 miles in the direction S 39.17°W. How far is the plane from the airport (round to the nearest mile)?

Answer 1

cos B=(c^2+a^2-b^2)/2ca

Answer 2

here angle B=90+39.17=129.17

Answer 3

cos(90+39.17)=-sin39.17
c=120
b=?
a=150
substitute the values and get the solution.