- ARP = RQ, but RC is longer than each of them
- BR divides PQ in the ratio of the two radii
- CRP = RC = RQ, and therefore ∠PCQ = 90°
- D∠PCQ is equal to the angle between the two radii drawn to C
Step-by-Step Solution
R is an external point of the first circle from which two tangents are drawn, touching at P and at C, so RP = RC. The same argument on the second circle gives RQ = RC. Hence RP = RC = RQ, so R is the midpoint of PQ and C lies on the circle whose diameter is PQ. An angle in a semicircle is a right angle, so ∠PCQ = 90°. The first option contradicts the equal-tangents theorem it should be using; the ratio option is what one would expect if R were on the line of centres instead; and the two radii to C are opposite rays, so the angle between them is 180°, not 90°.
Answer: C) RP = RC = RQ, and therefore ∠PCQ = 90°