A presentation on lines and angles for students of class 9.

1. Prepared by:
SHRITI GOYAL
IX – E
Roll no. 33

2.  An exact location
 It has no size, only position

3. Definition: When three or more points lie on a straight
line.
Illustration:
Notation: ABCD is a line.
Real life example: Cars parked in a straight line.

4. Definition: A line:
o is straight,
o has no thickness, and
o extends in both directions without end.
Illustration: A B
Notation: AB is a line. It can be extended to any
length.

5. Definition:
Illustration: A B
Notation: AB is a line segment with end points A
and B.
Real life examples: window panes are
surrounded by line segments all around

6. Definition: A line with a start point but no end
point.
Illustration:
A
Notation: A is the starting point but there is no
ending point.
Real life examples: A torch radiating light.

8. Definition: lines that intersect to form right
angles. m
Illustration:
n
Notation: m n
Key fact: Four right angles are
formed.

9. Real

10. Definition: A line that intersects two lines at
different points. t
Illustrations: m
n
Real life example:
Window pane

11.  It is a rotation of a line having starting but no
ending points.
Angles can be of many of many types::
 Basic angles
 Adjacent angles

13. Definition: Two angles are Adjacent when they
have a common side and a common vertex and
don't overlap. A
Illustration: B
D C
Notation: ADB is adjacent to BDC
> as they have a common vertex (D)
> and a common line (BD)

14. Defination: Two angles which are opposite to one
another.
Illustration: 1 2
3 4
5 6
7 8
Notation: Accordance to angle >>> 2 = 3
1 = 4
6 = 7
5 = 8

15. Definition: Two lines that form a line.
Illustration:
1 2
3 4
5 6
7 8
Notation: Accordance to angles >>> 1 + 2 = 180
3 + 4 = 180
5 + 6 = 180
7 + 8 = 180

16. Definition: Two angles that occupy corresponding
position.
Illustration: 1 2
3 4
5 6
7 8
Notation: 1 = 5
2 = 6
3 = 7
4 = 8

17. Definition: Two angles that lie between parallel
lines on opposite sides of the transversal.
Illustration:
1 2
3 4
Notation: 1 = 4
2 = 3

18. Definition: Two angles that lie outside the parallel
lines on opposite sides of the transversal.
Illustration:
1 2
3 4
Notation: 1 = 4
2 = 3

19. Definition: Two angles that lie inside the parallel
lines on the same sides of the transversal.
Illustration:
1 2
3 4
Notation: 1 + 4 = 180
2 + 3 = 180