Look at the figure below: an image of a right triangle is shown with an angle labeled y. if sin y° = a divided by 6 and tan y° = a divided by b, what is the value of cos y°?

The value of cos y is b/6
why?
when two fractions have the same denominator (number at the bottom), and the fractions are being divided, then the answer can be found by dividing the numerators - ignoring the denominators.
for example: (5/2) divided by (3/2) is equal to 5/3.
so here, it is known that tan y = a/b and sin y = a/6. also, the tan is equal to sin/cos. so, the cos should be b/6.
a/6 divided by b/6 is a/b, which is the tan