On a coordinate plane, parallelogram P Q R S is shown. Point P is at (5, 1), point Q is at (6, 4), point R is at (3, 10), and point S is at (2, 7). Which statement proves that PQRS is a parallelogram? The slopes of SP and RQ are both –2 and SP = RQ = StartRoot 45 EndRoot. The slopes of RS and QP are both 3 and SP = RQ = StartRoot 45 EndRoot. The midpoint of RP is (4, 5 and one-half) and the slope of RP is Negative nine-halves. The midpoint of SQ is (4, 5 and one-half) and SQ = 5.