Points (1, 1, 1), (–2, 4, 1), (–1, 5, 5) and (2, 2, 5) are the vertices of a
Rectangle
Square
Parallelogram
Trapezium
Let A = (1, 1, 1); B=(-2, 4, 1); C=(-1, 5, 5)& D =(2, 2, 5) AB = √9+9+0=3√2,BC=√1+1+16=3√2 and CD=3√2andAD=3√2. Hence it is a square.