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. $160°$
• B. $130°$
• C. $120°$
• D. $90°$

Answer: (D)

Verified step by step guidance

1. Recognize that the point (0, 1) lies on the unit circle, which means the radius from the origin to this point has length 1.
2. Recall that the unit circle is centered at the origin (0,0) and any point on it can be represented as (cos\theta, sin\theta), where \theta is the angle in standard position.
3. Since the point is (0, 1), set cos\theta = 0 and sin\theta = 1, and identify the angle \theta that satisfies these conditions.
4. Recall the special angles on the unit circle where sine equals 1 and cosine equals 0; this corresponds to the angle \theta = 90^\circ.
5. Conclude that the measure of the angle in degrees whose terminal side passes through (0, 1) on the unit circle is 90^\circ.