The given points are P(x1 y1) = (4, 8),
Q(x2, y2) = (5, 12) and R(x3,y3) = (9, 28).
∴ Slope of line PQ, m1 = \(\frac{12-8}{5-4}=4\)
And Slope of line PR, m2 = \(\frac{28-8}{9-4}=4\)
Since, slope of PQ = Slope of PR.
∴ The points P, Q and R are collinear