To find the x-value (cosine) at 150°, you can use the cosine function:
\[ \cos(150°) \]
First, note that 150° is in the second quadrant of the unit circle. The reference angle for 150° is:
\[ 180° - 150° = 30° \]
The cosine of 150° is the negative cosine of its reference angle, which is:
\[ \cos(150°) = -\cos(30°) \]
We know that:
\[ \cos(30°) = \frac{\sqrt{3}}{2} \]
Thus:
\[ \cos(150°) = -\frac{\sqrt{3}}{2} \]
Therefore, the x-value at 150° is:
\[ -\frac{\sqrt{3}}{2} \]