Question

if you take ZAOB = 2 COD, then
A AOB = A COD (Why?)
Can you now see that AB = CD?
EXERCISE 10.2
1. Recall that two circles are congruent if they have the same radii. Prove that equal
chords of congruent circles subtend equal angles at their centres.
2. Prove that if chords of congruent circles subtend equal angles at their centres, then
the chords are equal.
10.4 Perpendicular from the Centre to a Chord
Activity: Draw a circle on a tracing paper. Leto
be its centre. Draw a chord AB. Fold the paper along
a line through O so that a portion of the chord falls on
the other. Let the crease cut AB at the point M. Then,
ZOMA = ZOMB = 90° or OM is perpendicular to
AB. Does the point B coincide with A (see Fig.10.15)?
Yes it will. So MA = MB. .
IM
Fig. 10.15
ht triangles OMA​

Answer 1

Answer:

1.A per the theorem; equal chords (of a circle) subtend equal angles at the centre. Hence, it is clear that equal chords of congruent circles would subtend equal angles at their centres.

2.This is same as the previous question. The theorem says that if two chords subtend equal angles at centre then the chords are equal. Hence, if two chords in two congruent circles subtend equal angles at their centres then the chords are equal.