Find the angle which is equal to its supplementary angle

Question

Accepted Answer

To determine which angle is equal to its supplementary angle, we need to understand the concept of supplementary angles. Supplementary angles are two angles whose measures add up to 180 degrees.

1. **Explanation for Option 3 (90°):**
   - If an angle is 90 degrees, its supplementary angle must also be 90 degrees because 90° + 90° = 180°. This means that the angle is equal to its supplementary angle. Therefore, Option 3 is correct.

2. **Explanation for why other options are incorrect:**

- **Option 1 (45°):**
     - If an angle is 45 degrees, its supplementary angle would be 135 degrees because 45° + 135° = 180°. Since 45° is not equal to 135°, Option 1 is incorrect.

- **Option 2 (180°):**
     - If an angle is 180 degrees, its supplementary angle would be 0 degrees because 180° + 0° = 180°. Since 180° is not equal to 0°, Option 2 is incorrect.

- **Option 4 (360°):**
     - If an angle is 360 degrees, its supplementary angle would be -180 degrees because 360° + (-180°) = 180°. Since 360° is not equal to -180°, Option 4 is incorrect.

In conclusion, the only angle that is equal to its supplementary angle is 90 degrees, making Option 3 the correct answer.