Question

In the accompanying diagram, mZC = 90, mZA = 42, and CA = 10. Which equation can be used to find AB? A B 10 tan 42° = AB

Answer 1

We have to find AB.

As we have a right triangle, we can use trigonometric ratios to relate trigonometric functions with the length of the sides.

In this case, we use the angle
`\begin{gathered} \cos (\alpha)=\frac{\text{Adyacent}}{\text{Hypotenuse}} \\ \cos (A)=\cos (42\degree)=(AC)/(AB)=(10)/(AB) \\ \cos (42\degree)=(10)/(AB) \end{gathered}`Answer:

cos(42º)=10/AB [Option D]