Definitions
Point
A point has position but no dimensions, no length, no breadth and no height.
Line
A line has one dimension i.e., length only. It can be extended in both directions indefinitely.
or 'l' is a line
Line segment
A line segment has fixed length, it has two end points.
Ray
A ray can be extended in one direction only. Its other end is a fixed point.
A plane
A plane has length and breadth. It has two dimensions. Any flat surface is a plane.
In our study, we deal with figures drawn on plane surfaces.Axiom
Axiom is a statement that is accepted as true. It does not require any proof.
Theorem
Theorem is a statement that is accepted as true only after proving that it is a consequence of the axioms.
