This document defines and describes various parts of a circle including the radius, diameter, chord, arc, secant, and tangent. It explains that a circle is a closed curve where all points are equidistant from the center. A radius is a line from the center to the edge, a diameter connects two points on the edge passing through the center, and a chord connects any two edge points. An arc is part of the edge between two points, and a semicircle is half of a full circle. Secants and tangents are lines that intersect the circle at one or more points.

1. MATHEMATICSMATHEMATICS
GeometryGeometry
Circle and its
Parts

2. A circle

3. Many musical instruments have a circular surface.
For example:
Bingo Drum Tabla
Snare Drum Bass Drum

4. Five rings in the logo of Olympic games
A circle

5. A circle can be drawn with the help of a circular object.
For example: A circle drawn with the help of a coin.
A circle is a closed curve in a plane.

6. This fixed point (equidistant)
inside a circle is called
centre.
A circle is a closed curve
consisting of all points
in a plane which are at the
same distance (equidistant)
from a fixed point inside it.
OCentre
A circle
A circle has one and only
one centre.

7. Radius
A line segment that joins any point on the circle to its centre
is called a radius.
M
A point on the circle
CentreO
(Contd…)

8.  Radii ( plural of radius) of a circle are equal in length.
 Infinite number of radius can be drawn in a circle.
R
adius
Centre
K
O
L
M
N
(Contd…)

9. Diameter AB
A line segment that joins any two points on the circle and
passes through its centre is called a diameter.
A
B
A circle
O Centre
(Contd…)

10. A circle
O
M
 Infinite number of diameters can be drawn in a circle.
 As the radii of a circle are equal in length, its diameters too
B
Q
(Contd…)
Centre
P
A
N

11. The length of the diameter of a circle is twice the length of its
radius.
Radius OM
Centre
M
O
N
Radius ON
Diameter MN
Diameter MN = Radius OM + Radius ON
Radius OM = Radius ON
(Contd…)

12. A line segment that joins any two points on the circle is
called a chord.
O
B
A
A is a point on the
circle
B is another point
on the circle
A line segment that joins
point A and B
Chord

13. Diameter is also a chord of the circle.
O
Chord CD
C D
M
N
K
L
Chord MN
Chord KL
(Contd…)
Diameter CD

14. The diameter is the longest chord.
O
Diameter CD
C D
M N
Chord MN
(Contd…)
C D
M N
Chord KL
LK

15. L
K
M N
Chord MN
O Centre
Infinite number of chords can be drawn in a circle.
Chord KL
Chord
GH
G
H

16. K
C
O
Centre
Secant KC
KC
It is a line that intersects the circle at any two point
on the circle
line that contains a chord

17. K
C
O
Centre
Secant KC
KC
X
A
D
Infinite number of secants can be drawn in a circle.

18. K
C
O
Centre
It is a line that intersects the circle at exactly one
point on the circle. This point is called Point of
Tangency.
C
Point of
Tangency

19. O
Centre
An arc is the distance between any two points on the
circumference of a circle.
K L
(Contd…)

20. O
Centre
LK
An arc is named by three points, of which two are the end
points of the arc and the third one lies in between them.
X
Naming an arc
(Contd…)
Arc KXL

21. O
Centre
LK
X
Y
An arc divides the circle into two parts: the smaller arc is
called the minor arc, the larger one is called the major arc.
Minor Arc KXL
Major Arc KYL
(Contd…)

22. An arc
An arc

23.  Half of a circle is called a semicircle.
Centre
O
Diameter
D E
S
 A semicircle is also an arc of the circle.
R
Arc DSE
Semicircle DRE
(Contd…)
Semicircle DSE
Arc DRE

24. Radius Diameter Chord Arc
Semi
Circle
Centre
O

25. Radius Diameter Chord Arc
Semi
Circle
Radius O
M
Centre
M
O

26. Radius Diameter Chord Arc
Semi
Circle
Centre
ED
Diameter DE
O

27. Radius Diameter Chord Arc
Semi
Circle
Centre
Chord PQ
P
Q
O

28. Radius Diameter Chord Arc
Semi
Circle
Centre
E
G
Arc PQ
R
O
F

29. Radius Diameter Chord Arc
Semi
circle
S
Centre
O
Diameter
Semicircle
D E
Semicircle DSE
Semicircle

30. Secant Tangent
SecantMX
Centre
M
O
X

31. Secant Tangent
Centre
ED
Diameter DE
O
T
TangentDT
Point of Tangency

32. 1. the distance between any
two points on the
circumference of a circle.
2. A line segment that joins
any two points on a circle.
3..The line segment that joins
any two points on the
circle and passes through
its center.
4. Line segment that joins any
point on the circle to its
centre .
5. Line that intersects the
circle at any two point on
the circle.
6. line that intersects the circle
at exactly one point on the
circle
23 4
5
6
1
Direction: Fill in the box
the answers of its
corresponding statements
shown on the right.
Hint: The last letter of the
answer will be the first
letter of next answer.

33. Across:
1. the distance between any
two points on the
circumference of a circle.
2. A line segment that joins
any two points on a circle.
3..The line segment that joins
any two points on the
circle and passes through
its center.
4. Line segment that joins any
point on the circle to its
centre .
5. Line that intersects the
circle at any two point on
the circle.
6. line that intersects the circle
at exactly one point on the
circle
CHORDIA
M
E
T
E R A D I U S
E
C
ANTANGENT
R
A
Direction: Fill in the box
the answers of its
corresponding statements
shown on the right.
Hint: The last letter of the
answer will be the first
letter of next answer.