# Intersection of three plane when some are parallel.

- Author:
- Mark Willis

- Topic:
- Intersection

**1.**Look at the three equations of the plane. How do we know if they are parallel?;

**2.**Move the slider to see what happens when the third plane is no longer parallel;

**3.**Click to see the new equation of the third plane;

**4.**Use "Rotate 3d Graphics View" to view from a different perspective.