cos A = 24/25.
We know that the sine ratio is opposite/hypotenuse. This gives us 2 of the sides of the right triangle; one leg is 7 and the hypotenuse is 25. We can use the Pythagorean theorem to find the missing side:
7² + b² = 25²
49 + b² = 625
Subtract 49 from both sides:
49 + b² - 49 = 625 - 49
b² = 576
Take the square root of both sides:
√b² = √625
b = 24
Now that we have the adjacent side, we can find the cosine. Cosine is adjacent/hypotenuse:
24/25
