There is a plane that just took off and is climbing northwest through still air at an airspeed of 200 km/hr, and rising at a ate of 300 m/min. Resolve its velocity vector into components.

First, I converted 200 m/min to 18 km/hr so all values have the same units. Then I said the velocity of the plane would =

(-) 200 cos135degrees i + 200 sin135degrees j + 18 k

= - 141.42 i + 141.42 j + 18 k

However, the correct answer is - 140.8 i + 140.8 j + 18 k

Can someone please explain where I made my mistake? Thanks very much!