2 Answers

Khelll · Answer 1 · 2021-09-25T16:51:11+0000

Answer: B) 3/5

Explanation:

Cos = adjacent/hypotenuse

Thus, the cos is AC/AB.

Because of Pythagorean Theorem, AC^2=AB^2-BC^2. Let AC be x.

$x^2=10^2-8^2\\x^2=100-64\\x^2=36\\x=6$

Thus, the cos is 6/10, or 3/5

JSobell · Answer 2 · 2021-09-29T07:39:37+0000

Greetings from Brasil...

Here we have application of Trigonometry

COS β = adjacent side ÷ hypotenuse (H)

bringing to our problem....

COS A = AC ÷ H

But we dont have AC.... We have to use Pitagoras:

AB² = AC² + BC²

AC² = AB² - BC²

AC = √(AB² - BC²)

AC = √(10² - 8²)

AC = √(100 - 64)

AC = √36

So

COS A = AC ÷ H ⇔ COS A = AC ÷ AB

COS A = 6/10

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