The document defines key terms related to circles such as radius, diameter, chord, arc, semicircle, and segment. It explains that a circle is a closed curve where all points are equidistant from the center. A radius connects the center to any point on the circle, while a diameter connects two points on the circle and passes through the center. An arc is part of the circumference between two points on the circle. A semicircle is half of a circle, and a chord connects any two points on the circle. The document also provides examples of circles in daily life, music, and sports.
2. S
Centre
M
P
E
D
Q
G
O
F
Diameter DE
Circle in daily life
Circle in music
Circle in sports
Circle
Centre
Circumference
Circular region
Radius
Diameter
Chord
Arc
Semicircle
Segments of a circle
Crossword
4. Many musical instruments have a circular surface.
For example:
Bingo Drum Tabla
Snare Drum Bass Drum
BACK
5. Five rings in the logo of Olympic games
BACK
A circle
6. 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.
BACK
7. 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.
O
Centre
A circle
A circle has one and only
one centre.
8. The distance around a circle is called its circumference.
O
Centre
A circle
A
BACK
9. A circle divides a plane into three parts.
2. Interior of a circle
3. Exterior of a circle
A plane
O
Centre
The interior of a circle together with its circumference
is called the circular region.
1. The circle
BACK
10. A line segment that joins any point on the circle to its centre
is called a radius.
M
A point on the circle
Centre
O
(Contd…)
11. Radii ( plural of radius) of a circle are equal in length.
Infinite number of radius can be drawn in a circle.
Centre
K
O
L
M
N
(Contd…)
BACK
12. 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…)
13. 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
14. 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…)
BACK
15. 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
16. Diameter is also a chord of the circle.
O
Chord CD
C D
M
N
K
L
(Contd…)
Diameter CD
17. The diameter is the longest chord.
O
Diameter CD
C D
M N
Chord MN
(Contd…)
C D
M N
Chord KL
L
K
18. L
K
M N
Chord MN
O Centre
Infinite number of chords can be drawn in a circle.
G
H
BACK
19. O
Centre
An arc is the distance between any two points on the
circumference of a circle.
K L
(Contd…)
20. O
Centre
L
K
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
L
K
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…)
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
25. A chord divides the circular region into 2 parts, each of
which is called a segment of the circle.
Centre
O
D E
Chord DE
Minor segment of a circle
Major segment of a circle
S
R
(Contd…)
26. Centre
O
D E
Chord DE
Minor segment of
the circle
Major segment of the
circle
P
Q
Minor arc DPE
Major arc DQE
The part of the circular region enclosed by a minor arc and
the chord is called a minor segment.
Minor segment does not contain the centre of the circle.
The part of the circular region enclosed by a major arc and
the chord is called a major segment.
Major segment contains the centre of the circle.
BACK
32. Radius Diameter Chord Arc
Semi
circle
S
Centre
O
Diameter
Semicircle
D E
Semicircle DSE
Semicircle
33. C
2
C
U
M
F
E
R
N
C
E
A
E
I
Down
1. The distance between any two
points on the circumference of the
circle.
2. The distance around the circle.
3. The distance from the centre of the
circle to a point on the circle.
R
D
I
U
S
R
1
C
3R
A
Across:
4. The line segment that joins
any two points on the circle
and passes through its
centre.
5. A closed curve in a plane.
6. All points on the circle are
equidistant from this point.
7. A line segment that joins any
two points on a circle.
4D A M T
E E
5 I R L E
6C E N T E
H R
O D
7