Page 161 - Start Up Mathematics_5

Types of Lines

Besides being categorized as straight and curved, lines can be of various other types.

Intersecting lines
When two or more lines cross each other at a common point, A
they are called intersecting lines. The common point where A O C
they meet is called the point of intersection. All intersecting C O D D B
lines form angles at the point of intersection. In the given B
figures, AB and CD intersect at point O.

Perpendicular lines A

Two lines are said to be perpendicular if they meet or intersect at
right angles, i.e., the angle formed by the two lines is 90°. The symbol 90°
for perpendicular is ⊥. In the given figure, AB is perpendicular to PQ B
or AB ⊥ PQ. P Q

Parallel lines

You must have seen railway tracks. The two lines of the track
never meet each other. So, we say the tracks run parallel to
each other.

We define parallel lines as those lines which never meet
each other at a point. They are at equal distance from each
other. The symbol for parallel lines is .
In the given figures, AB is parallel to CD or AB CD. Parallel lines may be vertical, horizontal
or slanting. Rays and segments can also be parallel to each other.

A C
B

A B D
A
C D C Slanting
Horizontal B D

Vertical

XY and ST are not parallel because when extended, X Y
they meet at a point.
T

S

153