13. The point \(P ( p , 0 )\), the point \(Q ( - 2,10 )\) and the point \(R ( 8 , - 14 )\) lie on a circle, \(C _ { 2 }\)
Given that
- \(p\) is a positive constant
- \(Q R\) is a diameter of \(C _ { 2 }\)
find the exact value of \(p\).
(4)
(Total for Question 13 is 4 marks)