Answer:

Step-by-step explanation:
tan = opposite / adjacent
opposite side is the y-coordinate of a point on the terminal side
adjacent side is the x-coordinate of a point on the terminal side
if the terminal side is in the second quadrant (the top-left quadrant), a coordinate on the terminal side would have a negative x-coordinate and a positive y-coordinate
This being the case:
the opposite side (y) would be -3 and the adjacent side (x) would be 7
using the Pythagorean theorem:


The hypotenuse is c, so it equals 
sin = opposite / hypotenuse
so sin(theta) = 