Question 2 - A-Level Maths

The points \(P , Q\) and \(R\) have coordinates (-3, 7), (9, 11) and (12, 2) respectively.
1. Prove that angle \(P Q R = 90 ^ { \circ }\)
Given that the point \(S\) is such that \(P Q R S\) forms a rectangle,
find the coordinates of \(S\).