In a "right" triangle you have side lengths 13.1,12.3 and 4.4 centimeters. How would you find the other angles using sin,cos or tan?

Question

We have one right angle only and no other angles are given. Side lengths are 12.3cm, 13.1cm, and 4.4 cm.

I don't understand which side lengths are to be considered as adjacent while using the ratio. I want to use cos which is adjacent over hypotenuse. The hypotenuse is clear which is 13.1cm but I dont know what to use as my adjacent in the ratio.

Answer 1

The adjacent side is the side next to the angle in question (ignoring the hypotenuse , of course). The opposite side is the side you would run into if you drew an arrow from the center of the angle straight out to split the angle in half and extending to a side (the opposite side)

For angle A, the adjacent side is 4.4 and the opposite side is 12.3.

sin(A) = 12.3/13.1

cos(A) = 4.4/13.1

tan(A) = 12.3/4.4