3. What is
Geometry????!!!??
Geometry is the branch of
mathematics which deals with the
properties and relations of lines ,
angles , surfaces and solids. Just
as math's deals with numbers,
geometry deals with figures ,
points and lines…..
4. A point is usually represented by
a small dot and is name by a
single capital letter of
alphabet<see fig.1>.It has no
magnitude i.e. has no length,
breadth or thickness.
Fig.1
5. A line is straight and extends
indefinitely on both sides<see
fig.1>.
Fig.1
Line-
Line segment- A part of a line is called a
line segment.<see fig.2>.
Fig.2
A B
6. A ray is a part of a
line, which has one
end point, and
extends indefinitely
on the other
side<see fig.1>
A
7. A plane is a flat surface that
extends indefinitely in all
directions. The surface of the
wall is an example of a
plane.<see fig.1>.
Fig.1
8. An angle is formed by two
rays starting from the
same initial point. The
initial point O is called the
vertex. Rays OA and OB
are called the arms of the
angle.
O
A
B
9. A
C
B
A triangle is a three sided
closed figure, formed by
three line segments
intersect in pairs. A,B and
C are known as the
vertices (singular vertices)
of the triangle. A triangle
has:-
1.Three sides AB,BC and CA.
2.Three angles <A,<B and
<C.
3.Three vertices A, B & C
INTERIOR
EXTERIOR
NO
D
ALTITUDE
10. A quadrilateral is a four sided figure. ’
Quadri ’ means four, and ‘ lateral ‘
means sides. If A,B,C and D are four
points in a plane such that no three of
them are collinear and the line
segments AB,BC,CD and DA do not
intersect except at their end-points,
then the figure formed by these four
line segments is called the quadrilateral
ABCD.A D
B C
ADJACENT SIDES
BC & AD are
opposite sides.
11. .
o
A circles a set of points
on a plane which are at
the same distance from
a fixed point called
centre (O).
BA
OB=RADIUS
AB=DIAMETER< 2 X RADIUS >
INTERIOR
EXTERIOR
CHORD
C D
E
CED is the minor arc and CSD is
The major arc.
S
12. LEARNING OUTCOMES
Students will be able to
*understand the concept of a
point, line, line-segment, ray,
plane, angle, triangle,
quadrilateral, circle.
*apply the knowledge in different
situations.
