In AOPQ, OQ is extended through point Q to point R, m PQR = (4x -- 10), mZOPQ = (x +9)", and mZQOP = (x - 5)°. Find mZPQR.

1. ∠1 is complementary to ∠2 and ∠3 is complementary to ∠2. subtraction property of equality 2. m∠1 + m∠2 = 90 and m∠3 + m∠2 = 90 substitution 3. m∠1 + m∠2 = m∠3 + m∠2 definition of complementary 4. m∠1 = m∠3 given