I need help

Question

lyle has three points for a triangle ,where are the locations I should put the fourth point not to make a quadrilateral at all 

Answer 1

Given three points in a plane, defining a triangle (vertices are said given points), you can make a quadrilateral by choosing any new point not collinear with any of the triangle's sides.

 

Choosing a new point in the interior of the triangle, however, would seem to force the quadrilateral not to be convex, but that's OK with me since it is not expressly prohibited.