Question

the figure shows a unit circle in the ( xy )-plane, an angle ( alpha ) in standard position, and three labeled points. which of the following is the value of ( cos alpha )?
a ( -0.8 )
b ( -0.6 )
c ( 0.6 )
d ( 0.8 )

Explanation:

Step1: Recall unit circle cosine rule

For a point $(x,y)$ on the unit circle corresponding to angle $\alpha$ in standard position, $\cos\alpha = x$.

Step2: Identify x-coordinate of point A

The point $A$ on the unit circle is $(-0.8, 0.6)$, so its x-coordinate is $-0.8$.

Step3: Assign value to $\cos\alpha$

By the unit circle rule, $\cos\alpha = -0.8$.

Answer:

A. -0.8