COO020 · Coordinate geometry · Classes 6–12
Plane
A plane is a flat surface that extends forever in all directions. Three points that are not on one line fix exactly one plane.
Plane📐 Formula
Equation of a plane: ax + by + cz = d, with normal vector (a, b, c)
✏️ Worked example
The plane z = 0 is the floor of the 3D axes; its normal is (0, 0, 1).
🌍 Where it is used
Floors, table tops and sheets of paper model planes.
❓ Quick check
How many planes pass through three non-collinear points?