Q: 2 Prove that if chords of congruent circles subtend equal angles at their centres, then the chords are equal.
Given : chords of congruent circles subtend equal angles at their centres,
To prove : BC = QR
Proof :
In ABC and PQR,
BAC=QPR (Given)
AB = PQ (Radii of congruent circle)
AC = PR (Radii of congruent circle)
Thus, ABC PQR (By SAS rule)
BC = QR (CPCT)