If an angle in standard position has its terminal side pointing directly downward along the negative $y$-axis, what is its measure in degrees?

• A. $270°$
• B. $100°$
• C. $125°$
• D. $235°$

Answer: (A)

Verified step by step guidance

1. Recall that an angle in standard position starts from the positive x-axis and rotates counterclockwise.
2. Identify the direction of the terminal side: pointing directly downward along the negative y-axis.
3. Understand that the positive y-axis corresponds to 90\degree, so moving downward to the negative y-axis means rotating 180\degree more from the positive y-axis.
4. Calculate the angle measure by adding 180\degree to 90\degree, which gives the total rotation from the positive x-axis to the negative y-axis.
5. Conclude that the angle measure is 270\degree.