The two acute angles of a right triangle have degree measures of x and y. If sinx = 5/13, what is the value of cos y?

2 Answers
May 18, 2018

cos y = 5/13

Explanation:

x and y are complementary.

sin x = 5/13 = (opp)/(hyp)

However, the side opposite (opp) the angle x is also the side adjacent (adj) to angle y.

cos y = (adj)/(hyp) = 5/13

May 18, 2018

5/13.

Explanation:

Clearly, x+y=90^@.

:. y=90^@-x.

:. cosy=cos(90^@-x)=sinx=5/13, as Respected Mr. Hsia

has readily derived!