Consider the given points, PQ‌‌=√1+1+16 ‌‌=3√2 And, QR‌‌=√9+9+0 ‌‌=3√2 And PR‌‌=√16+4+16 ‌‌=√36 ‌‌=6 This implies, PQ2+QR2‌‌=18+18 ‌‌=36 ‌‌=PR2 Also , PQ=QR This implies, PQR is a right angled isosceles triangle.