This document defines and describes basic geometric shapes and terms. It defines points, lines, rays, line segments, angles, polygons, quadrilaterals and various types of each. Points have no dimensions, lines are made up of infinite points, rays have one endpoint, line segments have two endpoints, angles are measures of rotation. Polygons are closed figures made of line segments and can be regular, convex or concave. Quadrilaterals specifically have four sides and four angles.

2.  Geometry
Geo Metrian
(Earth) (Measures)
Plane:- A plane surface is surface which lies
evenly with the straight lines on itself.
Point:- A point is a geometrical figure which
has no dimensions. That means it has no
part.
Line:- A line is the collection of infinite number
of points and extends endlessly in both the
directions. A line is denoted by small letters as
l,m,n etc. (or) two capital letters like “AB” (It is
breadth less length)

3. Ray:- A part of a line with one end point is
called a ray. Ray AB is denoted by “AB”
A B
Linesegment:- A part of a line with two end
points is called line segment. (or)
It is the smallest distance between two points.
Line segment AB is denoted by AB.
A B
Angle:- The amount of rotation done by the
initial ray about its end vertex is called as
angle. A
o B

4. Zero angle:- Measures 0o . O B A
Acute angle:- Measures above 00 and below
900. B B
A 0 0 A
Right angle:- Measures exactly 900

5. Obtuse angle :- Measures above 900 and below
1800
Straight angle:- Measures exactly 1800 .
A O B
Reflex angle:- Measures above 1800 and below
3600 . o A
B
Complete angle:- Measures 3600 .
O B A

6. Parallel Lines:- Non intersecting line (or) lines
which has no common point are called
parallel lines. Perpendicular distance between
them will be same at any point.
Transversal:- The line intersecting another pair
of lines at two distinct points is called
transversal.
Angles made by the transversal on parallel
lines:-

7. Polygon is a simple closed figure made up of line
segments.
Examples:- Triangle, Quadrilateral, Pentagon
Hexagon, Heptagon, octagon etc.
Equilateral polygon:- A polygon in which all sides
are equal.
Example:- Equilateral triangle, Square, Rhombus
etc.
Equiangular polygon:- A polygon in which all its
interior angles are equal.
Example:- Equilateral triangle, square, rectangle
etc.

8. Regular polygon:- A polygon in which is both
the equilateral and equiangular is known as a
regular polygon.
Example:- Equilateral triangle, Square, Regular
pentagon etc.
Irregular Polygon:- A polygon in which angles
and sides are different.
Example:- Scalene Triangle, Trapezium etc.

9. Convex polygon:- A polygon in which each
of its interior angle measures below 1800 is
known as a convex polygon.
Example:- Triangle, Square, Rectangle etc.
Concave polygon:- A polygon in which one
of its interior angle is reflex angle is a
concave polygon.

10. A quadrilateral is a polygon made up of four
linesegments.
Four sides and four angles are the
elements/components/parts of the
quadrilateral.