Basic Geometrical Ideas Notes

In this page we have Basic Geometrical Ideas Class 6 Notes. Hope you like them and do not forget to like , social share and comment at the end of the page.


  • A point determines a location.
  • It is usually denoted by a capital letter
    Point in Geometry | Notes for Class 6 Maths Chapter 4: Basic Geometrical Ideas

Line segment

Line Segment
  • A line segment corresponds to the shortest distance between two points.
  • The line segment joining points A and B is denoted by $ \overline{AB}$.


Line in Geometry Class 6
  • A line is obtained when a line segment like AB is extended on both sides indefinitely
  • it is denoted by $\overleftrightarrow {AB}$ or sometimes by a single small letter like l.
  • A line is a one-dimensional figure that is made up of an infinite number of points and extends infinitely in both directions. It is often denoted by the symbol l


A Ray
  • A ray is a portion of line starting at a point and going in one direction endlessly.
  • It is represented as $ \overrightarrow{AB}$, where
  • A is the starting point and
  • B is another point on the ray.

Open Figures

An open figure is a shape that does not completely enclose a space. Examples include a line and a ray.
Open Figures

Closed Figures

A closed figure, on the other hand, completely encloses a space. Polygons like triangles, rectangles, and circles are examples of closed figures.
Closed Figures

Interior and Exterior of Closed Figures

The interior of a closed figure refers to the area enclosed by the figure. The exterior is the area outside the closed figure but within the common boundary.
Interior and Exterior of Closed Figures

Curvilinear Boundaries

Curvilinear boundaries are boundaries formed by curved lines, like the boundary of a circle.
Curvilinear Boundaries

Linear Boundaries

Linear boundaries are boundaries formed by straight lines, as seen in polygons like triangles, rectangles, and squares.


  • Angles:An angle is made up of two rays starting from a common initial point
  • Vertex:The vertex of an angle is the point where two lines, rays, or line segments meet.
  • Arm:The arms or the sidesare the two lines, rays, or line segments that form the angle.
  • The angle name is given by the point on the sides and vertex.
  • Here the angle is $\angle POQ$
  • Note that in specifying the angle, the vertex is always written as the middle letter.

Interior and Exterior of Angle

The interior of an angle is the space between the arms, and the exterior is the space outside the arms but within the angle's extensions.
Interior and Exterior of Angle

What is Polygon

  • A polygon is simple closed figure made up entirely of line segments.
    What is Polygon
  • Sides: The line segments forming a polygon are called its sides.Here $ \overline{AB}$,$ \overline{BC}$,$ \overline{CD}$, $ \overline{DE}$, $ \overline{EA}$
  • Vertex : The meeting point of a pair of sides is called its vertex. A,B,C,D,E
  • Adjacent sides: Any two sides with a common end point are called the adjacent sides of the polygon. Example $ \overline{AB}$ & $ \overline{BC}$ and $ \overline{CD}$ & $ \overline{DE}$
  • Adjacent vertices:The end points of the same side of a polygon are called the adjacent vertices. Vertices A and B are Adjacent. Similarly B and C are Adjacent
  • Diagonals: The joins of vertices which are not adjacent are called the diagonals of the polygon. AD, AC, EC,BD and BE are diagonals here

Also Read

Class 6 Maths Class 6 Science

Practice Question

Question 1 What is $\frac {1}{2} + \frac {3}{4}$ ?
A)$\frac {5}{4}$
B)$\frac {1}{4}$
D)$\frac {4}{5}$
Question 2 Pinhole camera produces an ?
A)An erect and small image
B)an Inverted and small image
C)An inverted and enlarged image
D)None of the above

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