In right ∆PQR, P and Q are acute angles, and cos P is 3/5. What is sin Q

We are given with a right triangle with two acute angles. In this case, since the triangle is a right one, the two other angles are complementary. Hence teh two angles should sum up to 90. In this case, the cos theta 1 is equal to sin theta 2 where the thetas are the two acute angles. The answer thus is 3/5.