Page 3 - Activity 2 Angle formed at center by an arc Ch.10 Circle

1. Take a rectangular piece of cardboard of suitable size and by using adhesive, paste
a white paper on it.
2. Cut out a circle of suitable radius with centre O from drawing sheet and paste it on
the cardboard.
3. Take a pair of points O and R on the circle to obtain the arc QR. (see Fig. 23.3)

4. To obtain the angle subtended by arc QR at centre O, join the points O and R to the
centre O. (see Fig. 23.3)
5. Taking a point P on the remaining part of circle, join it to Q and R to get ∠QPR
subtended by arc QR on point P on the remaining part of circle, (see Fig. 23.3)
6. Mark ∠QPR and ∠QOR.
7. Make a cut out of ∠QOR and a pair of cut outs of ∠QPR using transparent sheet,
(see Fig. 23.4)

8. Now, place the pair of cut outs of ∠QPR on the cut out of ∠QOR, adjacent to each
other, (see Fig. 23.5)