Table of contents  
Points  
Line Segment  
Line  
Intersecting Lines  
Parallel Lines  
Ray  
Curves  
Polygons  
Angles 
It is a position or location on a plane surface, which are denoted by a single capital letter.
It is a part of a line with the finite length and 2 endpoints.
The points A and B are called the endpoints of the segment.
It is named as:
It is made up of infinitely many points with infinite length and no endpoint.
It extends indefinitely in both directions. Named as:
The two lines that share one common point are called Intersecting Lines. This shared point is called the point of intersection.
Here, line l and m are intersecting at point C.
Real life example of intersecting lines:
Two or more lines that never intersect (Never cross each other) are called Parallel Lines.
Real life examples of parallel lines:
It is a part of a line with one starting point whereas extends endlessly in one direction.
Real life examples of the ray are:
Anything which is not straight is called a curve.
1. Simple Curve – A curve that does not cross itself.
2. Open Curve – Curve in which its endpoints do not meet.
3. Closed Curve – Curve that does not have an endpoint and is an enclosed figure.
A closed curve has 3 parts which are as follows
1. Interior of the curve
It refers to the inside/inner area of the curve.
The blue coloured area is the interior of the figure.
2. The exterior of the curve.
It refers to the outside / outer area of the curve.
The point marked A depicts the exterior of the curve.
3. The boundary of the curve
It refers to the dividing line thus it divides the interior and exterior of the curve.
The black line which is dividing the interior and exterior of the curve is the boundary.
The interior and boundary of the curve together are called the curves “region”.
It is a 2d closed shape made of line segments / straight lines only.
A figure formed from 2 rays which share a common endpoint is called Angle.
The rays forming the angle are known as its arms or sides.
The common endpoint is known as its vertex.
An angle is also associated with 3 parts
While naming an angle the letter depicting the vertex appears in the middle.
Example
The above angle can also be named as ∠CBA.
It is a 3 sided polygon. It is also the polygon with the least number of the sides.
Vertices: A, B and C
Sides: AB, BC and CA
Angles: ∠A, ∠B and ∠C
It is a 4 sided polygon
Vertices: A, B, C, D
Sides: AB, BC, CD, DA
Angle: ∠A, ∠B, ∠C, ∠D
Opposite Sides: AB and DC, BC and AD
Opposite Angles: ∠B and ∠D, ∠A and ∠C
Adjacent Angles: ∠A and ∠B, ∠B and ∠C, ∠C and ∠D, ∠D and ∠A.
It is a simple closed curve and is not considered as a polygon.
Parts of CirclesA diameter divides the circle into two semicircles. Hence the semicircle is the half of the circle, which has the diameter as the part of the boundary of the semicircle.
94 videos347 docs54 tests

1. What are the basic geometrical ideas taught in class 6? 
2. What is the difference between a line segment and a line? 
3. How do intersecting lines differ from parallel lines? 
4. What are rays in geometry? 
5. What are polygons and how are they different from curves? 

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