Physics Conservation of Momentum Problem with Vectors

A 1985 kg Oldsmobile traveling west on Saginaw Street at 15.9 m/s is unable to stop on the ice covered intersection for a red light at Abbott Road. The car collides with a 3804 kg truck hauling animal feed south on Abbott at 9.7 m/s. The two vehicles remain locked together after the impact. Calculate the velocity of the wreckage immediately after the impact. Give the speed for your first answer and the compass heading for your second answer. (remember, the CAPA abbreviation for degrees is deg)

So, for the velocity, I got 11.826 m/s. I used m1v1+m2v2=m1+m2(V) and solved for V. However, I don't know what to do for the second part.

To keep in line with the Cartesian coordinate system, set West as the -x direction (i) and South as the -y direction (j)

m1 = 1985 kg
m2 = 3804 kg

v1i = -15.9 i + 0 j m/s
v2i = 0 i - 9.7 j m/s

Conservation of mometum
m1+v1i + m2*v2i = (m1+m2)*vf

vf = ( m1*v1i + m2*v2i ) / (m1 + m2)

X-direction
vfx = ( m1*v1i + 0 ) / (m1+m2)
vfx = (1985 kg*-15.9 m/s) / (1985 kg + 3804 kg)
vfx = -5.45 m/s

Y-direction
vfy = ( 0 + m2*v2i ) / (m1+m2)
vfy = (3804 kg * -9.7 m/s) / (1985 kg + 3804 kg)
vfy = -6.37 m/s

|vf| = sqrt(vfx^2 + vfy^2) = 8.38 m/s

direction (Cartesian) = atan (vfy / vfx) = 229.5 degrees

To convert to compass, simply subtract 180, 49.5, and the 49.5 is below the x axis so subtract that from 270 deg, which corresponds with the -x axis

Compass = 220.5 deg