Rohit says that because PQ = QR, the points P(2, 3), Q(6, 6) and R(11, 6) must lie on one straight line. Test his claim with the distance formula.

$PQ=\sqrt{(6-2{)}^2+(6-3{)}^2}=\sqrt{16+9}=5$ and $QR$ = |11 - 6| = 5, so the two are indeed equal. But $PR=\sqrt{(11-2{)}^2+(6-3{)}^2}=\sqrt{81+9}=\sqrt{90}=3\sqrt{10}\approx 9.49$, while $PQ+QR=10$. Since no sum of two distances equals the third, $P,Q$ and $R$ form a genuine triangle. Equal distances only mean $Q$ is the same distance from each end, which happens for every point on the perpendicular bisector of $PR$.