Question

If Sin0=3/5, then cos0=?
Apex

Answer 1

4/5

Explanation:

I believe you meant sin Ф = 3/5, since sin 0 = 0 (zero).

sin Ф = 3/5 = (opposite side) / (hypotenuse).

cos Ф = (adjacent side) / (hypotenuse)

Use the Pythagorean Theorem to find the length of the adjacent side:

(adj)² + (opp)² = (hyp)² becomes (adj)² = 5² - 3² = 25 - 9 = 16.

Then (adj) = +√16 = +4

and so cos Ф = (adj) / (hyp) = 4/5