The supplement of a right angle is ..............

Options

A. `80^@`
B. `90^@`
C. `30^@`
D. `70^@`

Answer

To find the supplement of a right angle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Supplementary Angles**:
- Supplementary angles are two angles whose sum is equal to 180 degrees.

2. **Identify the Right Angle**:
- A right angle is defined as an angle that measures 90 degrees.

3. **Set Up the Equation**:
- Let’s denote the right angle as \( A \) (which is 90 degrees) and the supplementary angle as \( B \).
- According to the definition, we can write the equation:
\[ A + B = 180^\circ \]
- Substituting the value of \( A \):
\[ 90^\circ + B = 180^\circ \]

4. **Solve for \( B \)**:
- To find \( B \), we can rearrange the equation:
\[ B = 180^\circ - 90^\circ \]
- Simplifying this gives:
\[ B = 90^\circ \]

5. **Conclusion**:
- Therefore, the supplement of a right angle is also a right angle, which measures 90 degrees.

### Final Answer:
The supplement of a right angle is 90 degrees.