Which of the following statement is/are true about location of center of mass

The center of mass of four particles of equal weight placed at the vertices of a quadrilateral coincides with centroid of quadrilateral

The center of mass of three particles of same weight placed at the vertices of a triangle ABC coincides with the centroid of triangle ABC  

The center of mass of a body can exist outside the material of the body

A uniform wire is bent to form the sides of a triangle ABC the center of mass of wire coincide with centroid of triangle ABC