Question

If angle X and Y are complementary angles, which of the following must be true?

Answer 1

Answer:

D) Cos X = Sin Y

Step-by-step explanation:

If angle X and Y are complementary angles, as shown in the attachment, then;

$\cos X=\frac{a}{b}$

and

$\sin Y=\frac{a}{b}$

We can see clearly that both ratios are the same.

This implies that:

$\cos X=\sin Y$

Therefore the correct answer from the given options is D