Trig
posted by MEGGG!!! .
A swimmer heads perpendicular to a 2milesperhour current. His speed in still water is 1.8 miles per hour. Find the actual speed of the swimmer and his direction angle, 0 (the zero right here is supposed to have a line through the middle of it, I think it means cosine or something), with respect to the direction of the current.

Downstream, he is going with current, 2mph. Crosswise, he is going 1.8mph.
Draw the diagram. I see TanTheta=1.8/2.0
His actual speed?
speed=sqrt(2^2+1.8^2) or
speed=2.0/sinTheta