Page 148 - Math_Genius_V1.0_C4_Flipbook

E:\Working\Focus_Learning\Math_Genius_4_(25-10-2023)\Open_Files\Chap-08
\\December 6, 2023 12:54 PM Bharat Arora P-6 Reader _________________________ Date: ___________________

Perpendicular Lines: When a vertical line meets or intersects C
a horizontal line, they are called perpendicular lines.

In the given figure, vertical line AC intersects horizontal line
AB at point A. So, AC and DB are perpendicular lines. D A B

anGLe

When two rays or straight lines meet or intersect at a point, they form an angle.
The rays forming the angle are called the arms of the A

angle. Arm
The common point is called the vertex of the angle.

In the given figure, OA and OB are arms of the angle
AOB. O is the vertex of the angle AOB. Angle
O B
The symbol for an angle is ‘∠’. Thus, we write it as Vertex Arm
∠AOB and read as ‘angle AOB’. It can also be written

as ∠BOA. Note that the vertex of the angle is always written in the middle.

Think and Answer
Where do you see the angle around you? Write in the given blank space.

________________ ________________ ________________ ________________

Practice time 8B

1. Identify parallel, perpendicular and intersecting lines in the following figures.

(a) (b) (c)

(d) (e) (f)

2. Name the arms, vertex and the angle so formed in each of the following figures.
(a) O (b) (c)
A
C R
P
B
A B

Q

146 Mathematics-4