If a point lies in xz-plane, what is its y co-ordinate ?

Explanation

To determine the y-coordinate of a point that lies in the xz-plane, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Coordinate System**:
- The three-dimensional coordinate system consists of three axes: the x-axis, the y-axis, and the z-axis.
- The xz-plane is formed by the x-axis and the z-axis, while the y-axis is perpendicular to this plane.

2. **Identifying the xz-plane**:
- The xz-plane includes all points where the y-coordinate is constant. Specifically, in the xz-plane, the y-coordinate is always 0.
- This means any point in the xz-plane can be represented as (x, 0, z), where x and z can take any real values.

3. **Conclusion**:
- Since the y-coordinate is always 0 for any point lying in the xz-plane, we conclude that the y-coordinate of a point in the xz-plane is 0.

### Final Answer:
The y-coordinate of a point that lies in the xz-plane is **0**.

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