Page 208 - Maths Class 06

D

Step 4. Join B and D to get the BD.

Then, ÐABD = ÐDBC = 90° is the required angle.
90°
A P B Q C
Fig. 14.50
To Construct an Angle of 120°
B C
¾®
Step 1. Draw a ray BC. Fig. 14.51

Step 2. Tak ing B as the cen tre and with any suit able P
¾® B C
ra dius, draw an arc PQ cut ting BC at Q. Q
Fig. 14.52

Step 3. Tak ing Q as the cen tre and BQ as a ra dius draw S R
an arc cut ting arc PQ at R. P

Tak ing R as the cen tre and with the same ra dius, B Q C
cut an arc PQ at an other point S. Fig. 14.53
A

¾® R
Step 4. Join BS and pro duce it to get BA. S
Step 5. ÐABC is the re quired an gle of mea sur ing 120°. P 120°

B Q C
Fig. 14.54
To Construct an Angle of 30°
C

Q
Step 1. Draw an an gle of 60° as ex plained be fore (Fig. 14.55).

A B
P
Fig. 14.55
C
Step 2. Tak ing P as the cen tre and ra dius greater than half of PQ,
draw an arc. Tak ing Q as the cen tre and with the same ra dius
Q
draw an other arc, cut ting the pre vi ous arc at D. D
C

E A P B
Q D
Step 3. Join A and D to get the line segment AD Fig. 14.56
¾®
and produce it to get AE. 30°
A B
P
Fig. 14.57
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