If an angle in standard position has its terminal side passing through the point $(0,1)$ on the unit circle, what is its measure in degrees?

• A. $78°$
• B. $84°$
• C. $90°$
• D. $96°$

Answer: (C)

Verified step by step guidance

1. Recognize that the point (0, 1) lies on the unit circle, which means the radius (or hypotenuse) from the origin to this point has length 1.
2. Recall that the coordinates of a point on the unit circle correspond to (cos \theta, sin \theta), where \theta is the angle in standard position.
3. Since the point is (0, 1), this means cos \theta = 0 and sin \theta = 1.
4. Identify the angle \theta where cosine is 0 and sine is 1. This corresponds to the angle where the terminal side points straight up along the positive y-axis.
5. Conclude that the measure of the angle \theta in degrees is 90°, because that is the angle where the terminal side passes through (0, 1) on the unit circle.