1. The problem statement, all variables and given/known data A boat can go 12 km /h in a river that has current of 5 km /h. At what angle relative to the shore does the boat have to leave to arrive directly across from initial location? 2. Relevant equations SOH CAH TOA 3. The attempt at a solution I just want some explanation of this question. Would my 12km/h be my hypotenuse and the resultant be the straight line across the river perpendicular to the shore or would my 12km/h be the straight line perpendicular to the shore?? Because I get 2 different angles if I use tan-1 (5/12) = 22.16 degrees and sin-1 (5/12) which gives me 24.6 degrees.... Which one do I use?