In standard position, which ray is the terminal side of a $0°$ angle?

• A. The negative $x$-axis
• B. The negative $y$-axis
• C. The positive $y$-axis
• D. The positive $x$-axis

Answer: (D)

Verified step by step guidance

1. Recall that an angle in standard position is drawn with its vertex at the origin and its initial side along the positive x-axis.
2. Understand that the measure of the angle is the amount of rotation from the initial side to the terminal side, measured counterclockwise for positive angles.
3. For a 0° angle, there is no rotation from the initial side, so the terminal side coincides with the initial side.
4. Since the initial side is along the positive x-axis, the terminal side of a 0° angle is also along the positive x-axis.
5. Therefore, the ray representing the terminal side of a 0° angle lies on the positive x-axis.