Find the ratio for cos C.

Right triangle ABC. sideBC=36, CA=39, AB=15

Find the ratio for cos C.

Right triangle ABC. sideBC=36, CA=39, AB=15

13/5

12/13

13/12

5/13

1 answer

In a right triangle, the cosine of an angle is equal to the adjacent side divided by the hypotenuse. In this case, angle C is the right angle, so the cosine of angle C would be AC/AB.

Using the Pythagorean theorem, we can find the length of side AB:
AB^2 + BC^2 = CA^2
15^2 + 36^2 = 225 + 1296 = 1521
AB = √1521 = 39

Therefore, cos C = 15/39 = 5/13

So, the ratio for cos C is 5/13.