In ΔABC and ΔPBQ, ∠B = ∠B Common ∠BCA = ∠BQP {corresponding angles} ∠BAC = ∠BPQ {corresponding angles} ∴ ΔABC ≅ ΔPBQ {by Rule AAA} In ΔCPQ and ΔPQR, ∠Q = ∠R = 90° PQ = PQ Common ∠P = ∠P ⇒ ΔCPQ ≅ ΔPQR by Rule {ASA} And ΔCRQ and ΔCQP ∠R = ∠Q = 90° ∠Q = ∠Q = common. ∠C = ∠C = common ⇒ ΔCRQ ≅ ΔCQP {by Rule {ASA}}