Page 91 - Maths Skill - 6

Lines and Angles 89

COMPARISON OF ANGLES
We can compare two given angles by tracing paper as explained in the following example.

Let’s Attempt

Example 1: Compare the angles ∠PAQ and ∠LOR as given below.

R
Q

O

A
P L

Solution: Trace ∠LOR on a paper. Place the tracing of ∠LOR on ∠PAQ such that O falls on A and OL falls

along AP . Since AQ falls in the interior of ∠LOR

So, ∠LOR > ∠PAQ
R
Q

O(A) L(P)

MEASUREMENT OF ANGLES
We measure angles in degrees. The symbol for degree is ‘°’. A complete turn around a point is divided into 360
equal parts. Each of these parts is called a degree and is denoted by 1°. We use a special geometrical tool to
measure angles called protractor. It looks like as shown below.

Centre base line

The protractor is in the shape of a semi-circle and the midpoint of its horizontal edge or base line is called its
centre. A protractor has two scales—inner and outer. One scale begins with 0° on the right and moves to 180°
on the left. The other scale starts with 0° on the left and moves to 180° on the right. The smallest division on a
protractor is equal to 1°. To measure an angle ∠ABC using protractor, we follow these steps: