Question

Boating across a river, the current moves you downstream. Instead of going directly across the river, the boat moves at a 10 degree angle. If the river is 420 feet across, how far downstream will you end up?

Answer 1

To solve this problem, we use the tan function. The distance across the river is the adjacent side, the distance drownstream is the opposite side while the direction of the boat is the hypotenuse.

tan θ = opposite side / adjacent side

tan 10 = opposite side / 420 ft

opposite side = 74.06 ft

Therefore the boat will move about 74 ft downstream.