Is ||gm ABCD a square?
I. Diagonals of ||gm ABCD are equal.
II. Diagonals of ||gm ABCD intersect at right angles.

Options

A. if the question can be answered by one of the given statements alone and not by the other,
B. if the quesiton can be answered by either statement alone,
C. if the question can be answered by both the statements together but not by any one of the two,
D. if the question cannot be answered by using both the statements together.

Answer

C

Explanation

When the diagonals of a ||gm are equal, it is either a rectangle or a square. Also, if the diagonals intersect at right angles then out of rectangle and square, it is a square.
`therefore` both I and II will give the answer.
Hence, the correct answer is (c ) .