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E:\Working\Focus_Learning\Math_Genius_5_(05-10-2023)\Open_Files\CHAP_06
\\November 23, 2023 10:09 AM Surender Prajapati Proof 5 Reader _________________________ Date: ___________________74
parallel lines
When you travel by train, have you observed the railway track?
It looks like two straight lines which never meet at any point and
extended endlessly. It is an example of parallel lines.
Railway Track
Thus, the lines which lie in the same plane and never intersect are
called parallel lines.
Look at the two lines PQ and RS shown alongside.
If we extend these lines on both sides, we find that they do P Q
not intersect, even when we extend them to any extent.
Such lines are called parallel lines. R S
Two parallel lines are indicated by identical standing lines ||.
perpendicular lines
FACTS
Look at the pictures given below. In figures (i) and Parallel lines are always at the same
(ii), the objects make 90° angle from the ground distance apart.
Parallel lines lying on the same plane
and in figure (iii) the edges of the door meet at the never intersect each other.
corner make 90° angle.
Think and Answer
Look at your surroundings
and list the name of the
objects that represent:
1. Intersecting lines.
2. Parallel lines.
Fig. (i) Fig. (ii) Fig. (iii) 3. Perpendicular lines.
Thus, two lines which intersect each other making a right angle at the point of intersection
are called perpendicular lines.
f
In the adjoining figure, lines f and g are perpendicular to each other. A
The symbol ‘ ’ is used for perpendicular and is read as ‘‘is
90° 90°
perpendicular to”. g
C O D
We write it as f g or g f.
f ⊥ g or AB ⊥ CD or OA ⊥ CD or OB ⊥ CD B
teacher’s Explain the children that two straight lines intersect at one and only one point. Also, tell them that two lines
tip are coinciding if they have all points in common.
128 Mathematics-5
