Define axis of symmetry with the help of suitable figure.

Answer

### Step-by-Step Solution:

1. **Definition of Axis of Symmetry**:
The axis of symmetry is defined as a line that divides a figure into two equal halves. Each half is a mirror image of the other.

2. **Illustration of Axis of Symmetry**:
To illustrate this concept, let's consider a rectangle.

- Draw a rectangle on a piece of paper.
- Now, draw a vertical line down the center of the rectangle. This line is the axis of symmetry.

3. **Explanation of the Figure**:
- When you look at the rectangle, the vertical line divides it into two equal parts.
- Each side of the rectangle on either side of the axis of symmetry is identical in shape and size, which confirms that the line is indeed the axis of symmetry.

4. **Conclusion**:
Thus, the axis of symmetry for the rectangle is the vertical line that divides it into two equal halves.