Let A(1,5), B(5,8) and C(13,14) be the given points.
Distance formula = √((x2 - x1)2 + (y2 - y1)2)
AB=√((-)2 + (-)2)
=√
=
BC=√((-)2 + (-)2)
AC=√((-)2 + (-)2)
Here AC=AB+BC
Triangle ABC cant be formed with the given vertices.