PK 2016 Q2
2. Four of the following points are vertices of the same square. Which point is not a vertex of this square?
- A (−1, 3)
- B (0, −4)
- C (−2, −1)
- D (1, 1)
- E (3, −2)
Pink Kangaroo 2016, Question 2. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: A (−1, 3)
By plotting the points, it is easy to check that \(BCDE\) is a square. Since any three vertices of a square determine the fourth vertex, it is impossible to make a square using three of these points and the point \(A\).
Solution © UK Mathematics Trust, from the PK 2016 solutions.