Question

If vertices of any quadrilateral are (0, –1), (2,1), (0, 3) and (– 2,1), then it is a.

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

Answer 1

Answer: (B)

Square

Answer 2

Let $A ( 0 , - 1 ) , B ( 2,1 ) , C ( 0,3 )$ and $D ( - 2,1 )$

Obviously $A B = B C = C D = A D = 2 \sqrt { 2 }$

Also, $A C = B D = 4$ and slope of line $A B = 1$

Slope of line $A D = - 1$ . $\therefore \angle D A B = 90 ^ { \circ }$ .

Similarly, $\angle B = \angle C = \angle D = 90 ^ { \circ }$ i.e. each angle is right

angle. $\therefore$ Quadrialteral is a square.