Answer:
tan y°
Explanation:
by using the Sine Rule (See attached), we can form the equation:

rearranging this, we get:
---------------------eq 1
Recall that all internal angles of a triangle must sum to 180°. we observe that we have a right triangle where one of the angles is 90°. It then follows that the sum of the other two angles must sum to 90°
i.e x + y = 90°
with a little rearranging, we get
x = (90° - y)
Substituting this into eq 1 above, we get:
---------eq 2
recall that from the trigonometric co-function identities,
sin (90°- y) = cos y
substituting this into eq 2 gives :
(answer)