Answer:
c) 12/15 = 4/5
Step-by-step explanation:
imagine we mirror the triangle up, so that Z is on top.
then you can clearly see that 6 is cos(X) times r (and r is then 7.5).
XY is sin(X)×7.5
and again, 7.5 is r (the line making the X angle).
so, the cosine ratio of X is
6 = cos(X)×7.5
cos(X) = 6/7.5 or then 12/15. or simplified 4/5.
