i don't really understand your question because which side is the leg on?
anyway, if the leg (19.2) is adjacent to the angle (46), then you'd use cos
so the equation should be: cos(46 degrees)=19.2/x
but if the leg is opposite of the given angle, then you'd use sin
plus, you could use sin and cos reciprocals - sec and csc
just remember SOHCAHTOA