Q: 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.
Given: The two circles are congruent if they have the same radii.
To prove: The equal chords of congruent circles subtend equal angles at their centres i.e. BAC=QPR
Proof :
In ABC and PQR,
BC = QR (Given)
AB = PQ (Radii of congruent circle)
AC = PR (Radii of congruent circle)
Thus, ABC PQR (By SSS rule)
BAC=QPR (CPCT)