Answer:
The third choice
Step-by-step explanation:
Sin = (opposite side)/(hypotenuse)
Cos = (adjacent side)/(hypotenuse)
Tan = (opposite side)/(adjacent side)
The opposite side means the side that doesn't form the vertice of the angle. It's on the 'opposite' side of the triangle than the angle. In this case, the side opposite of angle Y is side XZ.
The adjacent side of an angle the side that forms the vertice of the angle, that is NOT the hypotenuse. In this case, the side adjacent to angle Y is side YZ
The hypotenuse is ALWAYS the longest side, and the side opposite of the 90° angle. The hypotenuse is side XY , so
Sin (Y) = XZ/XY
Cos (Y) = YZ/XY
and
Tan (Y) = XZ/YZ
