Answer:
48°
Step-by-step explanation:
You want the reference angle for 312°.
Reference angle
The reference angle is the positive angle between the terminal ray and the nearest branch of the x-axis.
Here, the terminal ray is in the 4th quadrant, so the nearest branch of the x-axis is the +x axis. The angle is the difference between 360° and 312°:
360° -312° = 48°
The reference angle for 312° is 48°.
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Additional comment
Mathematically, the reference angle is the minimum of the angle modulo 180°, and its supplement. This is shown in the second attachment.
