Question

which equation can be used to find b in the triangle?
cos b = \frac{10}{6}
cos b = \frac{10}{6}
tan b = \frac{8}{10}
tan b = \frac{8}{6}

Explanation:

Step1: Recall trigonometric - ratio definitions

In a right - triangle, $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$ and $\tan\theta = \frac{\text{opposite}}{\text{adjacent}}$. For angle $B$, the adjacent side to angle $B$ is $8$ and the hypotenuse is $10$, and the opposite side to angle $B$ is $6$.

Step2: Calculate cosine and tangent of angle $B$

$\cos B=\frac{\text{adjacent to }B}{\text{hypotenuse}}=\frac{8}{10}$, and $\tan B=\frac{\text{opposite to }B}{\text{adjacent to }B}=\frac{6}{8}$.

Answer:

$\cos B=\frac{8}{10}$