1. The problem statement, all variables and given/known data A plane flies at 400 km/h [south 30 degrees east]. The wind is blowing from the east at 100 km/h. Find the resulting speed of the plane. 2. Relevant equations Not sure 3. The attempt at a solution I've drawn a diagram similar to this: |\ | \ | \ |30\ | \ | \ 400 km/h | \ |_____\ 100km/h I thought this was just a simple question of finding the left side of the triangle, but I don't seem to get the answer. Any hints is greatly appreciated. Thank you in advance.