Question

Points (1, 1, 1), (–2, 4, 1), (–1, 5, 5) and (2, 2, 5) are the vertices of a

• A. Rectangle
• B. Square
• C. Parallelogram
• D. Trapezium

Answer 1

Answer: (B)

Square

Answer 2

Let $A = ( 1,1,1 )$;$B = ( - 2,4,1 )$;$C = ( - 1,5,5 )$ & $D = ( 2,2,5 )$

$A B = \sqrt { 9 + 9 + 0 } = 3 \sqrt { 2 } , B C = \sqrt { 1 + 1 + 16 } = 3 \sqrt { 2 }$ and

$C D = 3 \sqrt { 2 }$ and $A D = 3 \sqrt { 2 }$ Hence it is a square.