Remember SOHCAHTOA to write your trig functions. Remember H stands for hypotenuse, which is always the longest side. O stands for the sign opposite the angle, the side farthest away from it. A stands for the adjacent angle, the one that touches the angle. So with this knowledge, you can find each of the three trig functions. Then notice that the sine of one angle will equal the cosine of the other angle since the side adjacent to one angle is opposite the other one.