Q: 1 Prove that the line of centres of two intersecting circles subtends equal angles at the two points of intersection.
Given: Circle C(P,r) and circle C(Q,r') intersect each other at A and B.
To prove : PAQ = PBQ
Proof : In APQ and BPQ,
PA = PB (radii of same circle)
PQ = PQ (Common)
QA = QB (radii of same circle)
So, APQ BPQ (By SSS)
PAQ = PBQ (CPCT)