Question

Evaluate cosθ when sinθ = -7/8 and θ is in Quadrant IV.

Answer 1

Answer:

cosθ= $\frac{ \sqrt{15} }{8}$

Step-by-step explanation:

Please see attached picture for full solution.

In the 4th quadrant, the cosine of an angle is positive.

The opposite side takes the negative sign in -⅞ since it is below the x-axis. Likewise, we reject $x = - \sqrt{15}$ since x lies on the right side of the y axis.