Question

Hypotenuse of 15 and opposite of 12For this triangle what is the cos

Answer 1

Given

right triangle with side "a" = 12 and hypotenuse "c" = 15

Find

cos(∠A)

Solution

The Pythagorean theorem tells you

... b = √(c² - a²) = √(225 - 144) = √81 = 9

The definition of the cosine tells you

... cos(A) = b/c = 9/15

... cos(A) = 3/5 . . . . . . reduce the fraction