In a right triangle ABC, the ratio of the hypotenuse to the side adjacent to angle A is defined as?

Question

I answered "cos A" and I was wrong!! ideas? thanks

Answer 1

Remember SOH-CAH-TOA

Sin(A) = Opposite / Hypotenuse
Cos(A) = Adjacent / Hypotenuse
Tan(A) = Opposite / Adjacent

In your case you have the measures of the adjacent side and the hypotenuse.

Using the mnemonic above that would equate to:
cos(A) = adjacent / hypotenuse.

But you have the reciprocal, so invert everything:
1 / cos(A) = hypotenuse / adjacent

You could say 1/cos(A), but equivalently you can write:
sec(A)

Answer 2

Draw the diagram out first. If angle B is the right angle, then AB/AC=cosA
But you want AC/AB=1/cosA
So the ratio is 1/cos A or sec A

Answer 3

cosA = adj. side / hypotenuse

so hypotenuse / adj. side = 1/ cosA = secA