Page 188 - Maths Class 05

i. 90° = ________________ j. 180° = ________________

k. 75° = ________________ l. 150° = ________________
4. Identify the angles given below.

a. b. c. d.

_______________ _______________ _______________ _______________

e. f. g. h.

_______________ _______________ _______________ _______________

Constructing Angles with a Protractor

Protractor
To construct an angle A

Construct ÐABC = 75° 70 80 90 100 110
60 110 100 80 70 120
Step 1 : Draw a ray BC 50 120 60 130
40 130 50 140
Step 2 : Place the centre of the protractor on 30 150 140 40 30 150
20 160
160 20
the end point B of BC. Point B will form 10 170 10 170
0 180 0 180 C
the vertex point. B

Step 3 : Adjust the protractor such that base line is along BC.

Step 4 : Now, measure carefully from the 0° from opposite side of vertex point (from
the inner scale).

Step 5 : Mark point A at 75°.

Step 6 : Remove the protractor and join point A to point B, to get BA. The measure of

ÐABC = 75°.

Practice - 13.5
Practice - 13.5
Practice - 13.5
Practice - 13.5
1. Use a protractor to draw angles of.
a. 90° b. 145° c. 120° d. 135°

e. 45° f. 75° g. 180° h. 60°

Mathematics-5 188