The angles marked
x° and
y° are acute angles in a right triangle. Thus, they are complementary angles. By the complementary angle relationship between sine and cosine, it follows that
sin(x°)=cos(y°). Therefore, the cosine of
y° is .6. Either .6 or the equivalent fraction
may be gridded as the correct answer.
Alternatively, since the sine of
x° is .6, the ratio of the side opposite the
x° angle to the hypotenuse is .6. The side opposite the
x° angle is the side adjacent to the
y° angle. Thus, the ratio of the side adjacent to the
y° angle to the hypotenuse, which is equal to the cosine of
y°, is equal to .6.