CIRCLE
Objectives 
After completing this module, you will be able to, 
 Define a circle 
 Define circle basics (chord, segment , sector, acr, 
secant, etc) 
 Define intersecting line, non-intersecting line and 
tangent.
Circle (Basics) 
A circle is a shape with all points at the same distance from its 
A 
B E 
O 
= 
= 
= 
C D 
Radius 
It’s the distance from 
the center of a circle 
to any point on the 
circle. 
Diameter 
Centre 
of circle 
Circumference 
centre. 
It’s the distance across 
a circle through the 
center. 
All points on the circle are 
at same distance from the 
centre point. 
It’s the distance around 
the circle.
Chord 
A chord is a straight line segment with its end points on the 
circumference of a circle 
A 
Chord Chord 
B E 
O 
Diameter, 
the biggest chord 
Interior of 
the circle 
Exterior of the circle
Arc 
An arc is a part of a circumference of a circle. 
O 
M 
N 
Chord 
Major Arc 
Minor Arc 
Minor 
Segment 
Major 
Segment 
1 
2
Secant 
If the line segment that forms a chord of a circle is 
extended on both the sides, the straight line with two 
points on the circle is known as a secant. 
O 
A 
B 
Chor 
d 
Secant
Sector 
Sector of a circle is a portion of a circle enclosed by two radii and 
an arc. 
O 
Major 
Sector 
Radius Radius 
A B 
Minor 
Sector
Circle and a Line in a Plane 
O 
Secant 
Line AB and the circle 
have two common 
points M and N 
Tangent 
There is only one point P 
which is common to the 
line AB and the circle 
A 
B 
O 
M 
N 
O 
P 
Non-intersecting Line 
Line AB and the circle 
have no common points
Summary 
Let us revise what we have learnt in this session. 
 A circle is a collection of all points in a plane which are 
at a constant distance from a fixed point. 
 Radius is the distance from the center of a circle to any 
point on the circle. 
 Diameter is the distance across a circle through the 
center. 
 Circumference is the distance around the circle. 
 A chord is a straight line segment with its end points 
on the circumference of a circle
Summary 
 An arc is a part of a circumference of a circle. 
 If the line segment that forms a chord of a circle is 
extended on both the sides, the straight line with two 
points on the circle is known as a secant. 
 Sector of a circle is a portion of a circle enclosed by 
two radii and an arc. 
 Intersecting line have two common points & Non-intersecting 
line have no common points with the 
circle. 
 Tangent have only one common point with the circle.
Circle - Basic Introduction to circle for class 10th maths.

Circle - Basic Introduction to circle for class 10th maths.

  • 1.
  • 2.
    Objectives After completingthis module, you will be able to,  Define a circle  Define circle basics (chord, segment , sector, acr, secant, etc)  Define intersecting line, non-intersecting line and tangent.
  • 3.
    Circle (Basics) Acircle is a shape with all points at the same distance from its A B E O = = = C D Radius It’s the distance from the center of a circle to any point on the circle. Diameter Centre of circle Circumference centre. It’s the distance across a circle through the center. All points on the circle are at same distance from the centre point. It’s the distance around the circle.
  • 4.
    Chord A chordis a straight line segment with its end points on the circumference of a circle A Chord Chord B E O Diameter, the biggest chord Interior of the circle Exterior of the circle
  • 5.
    Arc An arcis a part of a circumference of a circle. O M N Chord Major Arc Minor Arc Minor Segment Major Segment 1 2
  • 6.
    Secant If theline segment that forms a chord of a circle is extended on both the sides, the straight line with two points on the circle is known as a secant. O A B Chor d Secant
  • 7.
    Sector Sector ofa circle is a portion of a circle enclosed by two radii and an arc. O Major Sector Radius Radius A B Minor Sector
  • 8.
    Circle and aLine in a Plane O Secant Line AB and the circle have two common points M and N Tangent There is only one point P which is common to the line AB and the circle A B O M N O P Non-intersecting Line Line AB and the circle have no common points
  • 9.
    Summary Let usrevise what we have learnt in this session.  A circle is a collection of all points in a plane which are at a constant distance from a fixed point.  Radius is the distance from the center of a circle to any point on the circle.  Diameter is the distance across a circle through the center.  Circumference is the distance around the circle.  A chord is a straight line segment with its end points on the circumference of a circle
  • 10.
    Summary  Anarc is a part of a circumference of a circle.  If the line segment that forms a chord of a circle is extended on both the sides, the straight line with two points on the circle is known as a secant.  Sector of a circle is a portion of a circle enclosed by two radii and an arc.  Intersecting line have two common points & Non-intersecting line have no common points with the circle.  Tangent have only one common point with the circle.

Editor's Notes

  • #2 Today we are going to revise some basic terms related to circles.
  • #3 Objectives: After completing this module, you will be able to, Describe a tangent to a circle Define circle basics(chord, segment, sector, arc, secant, etc) Define intersecting line, non-intersecting line and tangent.
  • #4 Let us revise the concept of a circle. This is a point O in a plane. A circle is a collection of all points in a plane which are at a constant distance from the point O. If A, B, C, D and E are the points of the circle, then, length OA is equal to length OB is equal to length OC is equal to length OD is equal to length OE. Point O is called centre of the circle. OA, OB, OC, OD and OE are the radii of the circle. BE is the diameter of the circle and this is arc is the circumference of the circle.
  • #5 Audio Script: A chord is a straight line segment with its end points on the circumference of a circle. If we join any two points on the circle, it is called as chord of a circle. Here, AB, AE and BE are the Chords of the circle. Diameter is the biggest chord of a circle. The portion inside the circle is known as interior of the circle while the portion outside the circle is known as exterior of the circle.
  • #6 Audio Script: An arc is a part of a circumference of a circle. If segment MN is a chord, then, Arc MN-1 is known as the minor arc and arc MN-2 is known as the major arc. The interior region of a circle between a chord and an arc of a circle is known as a segment.
  • #7 Audio Script: If the line segment that forms a chord of a circle is extended on both the sides, the straight line with two points on the circle is known as a secant.
  • #8 Audio Script: Sector of a circle is a portion of a circle enclosed by two radii and an arc. The area enclosed by radii and major arc is known as Major Sector and the area enclosed by radii and minor arc is known as Minor Sector.
  • #9 Audio Script: Let us now observe the different situations that can arise when a circle and a line are given in a plane. Consider a circle with centre O and a line AB. There can be three possibilities. The line AB and the circle have no common point. Then, the line AB is called a non-intersecting line with respect to the circle. There are two common points M and N that the line AB and the circle have. That is, the line AB intersects the circle in two points, M and N. Then, the line AB is called as a secant of the circle. There is only one point P which is common to the line AB and the circle. Then, the line AB is called a tangent to the circle.
  • #10 Audio Script Let us revise what we have learnt in this session. A circle is a collection of all points in a plane which are at a constant distance from a fixed point. If a circle and a line are given in a plane, then the line can be a non-intersecting line with respect to the circle or the line can be a secant of the circle. If there is only one point which is common to the line and the circle, the line is called a tangent to the circle. The tangent at any point of a circle is perpendicular to the radius through the point of contact.
  • #11 Audio Script Let us revise what we have learnt in this session. A circle is a collection of all points in a plane which are at a constant distance from a fixed point. If a circle and a line are given in a plane, then the line can be a non-intersecting line with respect to the circle or the line can be a secant of the circle. If there is only one point which is common to the line and the circle, the line is called a tangent to the circle. The tangent at any point of a circle is perpendicular to the radius through the point of contact.