Reference Angle in Unit Circle

Answer explanation

The reference angle is the acute angle formed with the x-axis. For 225°, the related reference angle is 225° - 180° = 45°, which is in the third quadrant. Thus, the correct answer is 45°.

Answer explanation

The reference angle is the acute angle formed with the x-axis. For 270°, the related reference angle is 90°, as it is directly downward on the y-axis.

Answer explanation

The reference angle for 300° is found by subtracting it from 360°, giving us 60°. Thus, the related reference angle is 60°.

Answer explanation

The reference angle is the acute angle formed with the x-axis. For 210°, the related reference angle is 210° - 180° = 30°, which is in the third quadrant.

Answer explanation

The reference angle is the acute angle formed with the x-axis. For 315°, the related reference angle is 360° - 315° = 45°, which is the correct choice.

Answer explanation

The reference angle is the acute angle formed with the x-axis. For 330°, subtract from 360°: 360° - 330° = 30°. Thus, the related reference angle is 30°.

Answer explanation

The reference angle is the acute angle formed by the terminal side of the angle and the x-axis. For 360°, the terminal side coincides with the positive x-axis, making the reference angle 0°.

Answer explanation

The reference angle is the acute angle formed with the x-axis. For 240°, the related reference angle is 240° - 180° = 60°, which is in the third quadrant. Thus, the correct answer is 60°.

 $180\degree$  State the related reference angle

•  $0\degree$  

•  $30\degree$  

•  $45\degree$  

•  $60\degree$  

•  $90\degree$  

 $135\degree$  State the related reference angle

•  $0\degree$  

•  $30\degree$  

•  $45\degree$  

•  $60\degree$  

•  $90\degree$