Angle Equal to its Supplement
Angle and its supplement are two angles whose measures add up to 180 degrees. When an angle is equal to its supplement, it means that the angle and its supplement have the same measure.

Explanation
- Let's consider an angle x.
- Its supplement will be 180 - x.
- If x = 180 - x, then the angle is equal to its supplement.
- Solving the equation, we get:
x = 180 - x
2x = 180
x = 90
Therefore, the angle which is equal to its supplement is 90 degrees. This angle is called a right angle.

Importance
- Understanding angles and their supplements is crucial in geometry and trigonometry.
- Identifying angles equal to their supplements helps in solving various geometric problems.
- Knowing properties of angles helps in constructing shapes accurately.
In conclusion, an angle equal to its supplement is 90 degrees. This concept is fundamental in geometry and plays a significant role in various mathematical applications.