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MATHEMATICMATHEMATICSS
GeometryGeometryCircle and its
PartsCircle and its
Parts
A circle
Many musical instruments have a circular surface.
For example:
Bingo Drum Tabla
Snare Drum Bass Drum
Five rings in the logo of Olympic games
A circle
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.
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.
Radiu
s
A line segment that joins any point on the circle to its centre is called a radius.
MA point on the circle
CentreO
(Contd…)
Radii ( plural of radius) of a circle are equal in length.
Infinite number of radius can be drawn in a circle.
Radiu
s
Centre
K
O
L
M
N
(Contd…)
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 circleO Centre
(Contd…)
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 are equal in length.
B
Q
(Contd…)
Centre
P
A
N
The length of the diameter of a circle is twice the length of its radius.
Radius OM
Centre
MO
NRadius ON
Diameter MN
Diameter MN = Radius OM + Radius ON Radius OM = Radius ON
(Contd…)
A line segment that joins any two points on the circle is called a chord.
O
BA
A is a point on the circle
B is another point on the circle
A line segment that joins point A and B
Chord
Diameter is also a chord of the circle.
O
Chord CDC D
M
N
K
L
Chord MN
Chord KL
(Contd…)
Diameter CD
The diameter is the longest chord.
O
Diameter CDC D
M NChord MN
(Contd…)
C D
M N
Chord KLLK
LK
M NChord MN
O Centre
Infinite number of chords can be drawn in a circle.
Chord KL
Chord GH
G
H
KC
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
KC
O
Centre
Secant KC
KC
X
A
D
Infinite number of secants can be drawn in a circle.
KC
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
O
Centre
An arc is the distance between any two points on the circumference of a circle.
K L
(Contd…)
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.
XNaming an arc
(Contd…)
Arc KXL
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…)
An arc
An arc
Half of a circle is called a semicircle.
CentreO
DiameterD E
S
A semicircle is also an arc of the circle.
R
Arc DSE
Semicircle DRE
(Contd…)
Semicircle DSE
Arc DRE
Radius Diameter Chord ArcSemiCircle
CentreO
Radius Diameter Chord ArcSemiCircle
Radiu
s OM
Centre
M
O
Radius Diameter Chord ArcSemiCircle
Centre
EDDiameter DE
O
Radius Diameter Chord ArcSemiCircle
Centre
Chord PQ
P
Q
O
Radius Diameter Chord ArcSemiCircle
Centre
E
G
Arc P
QRO
F
Radius Diameter Chord ArcSemicircle
S
CentreO
Diameter
Semicircle
D E
Semicircle DSE
Semicircle
Secant Tangent
Seca
nt M
X
Centre
M
O
X
Secant Tangent
Centre
EDDiameter DE
O
TTan
gen
t D
T
Point of Tangency
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
45
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.
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
CH
OR
DI
AM
ET E R A D I U S
E
CA
NT
AN
GE
NTR
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.
