-->

Surface Areas And Volumes

Question
CBSEENMA9003178

Construct the angles of the following measurements:

15°

Solution

15°

Given: A ray OA.

Required: To construct an angle of 15° at O.
Steps of Construction:
1. Taking O as centre and some radius, draw an arc of a circle, which intersects OA, say at a point B.
2. Taking B as centre and with the same radius as before, draw an arc intersecting the previously drawn arc, say at a point C.

3. Draw the ray OE passing through C.

Then ∠EOA = 60°.

4. Now, taking B and C as centres and with the radius more than 1 half BC, draw arcs to intersect each other, say at D.

5. Draw the ray OD intersecting the arc drawn in step 1 at F. This ray OD is the bisector of the angle EOA, i.e., ∠EOD = ∠AOD
equals 1 half angle EOA equals 1 half left parenthesis 60 degree right parenthesis equals 30 degree

6. Now, taking B and F as centres and with the radius more than 1 half BF, draw arcs to intersect each other, say at G.
7. Draw the ray OG. This ray OG is the bisector of the angle AOD, i.e., ∠DOG =

angle AOG equals 1 half angle AOD equals 1 half left parenthesis 30 degree right parenthesis equals 15 degree.