In the given figure ABCD is a parallelogram, angles DAB and ABC are in the ratio 5 : 7, the value of x is:

1. 105°

2. 85°

3. 75°

4. none of these

ABCD is a rectangle. To make it a square which of the following condition(s) must be satisfied:

1. AC = BD

2. AC ⊥ BD

3. Diagonals bisect each other

4. AB = CD

The diagonals of a quadrilateral are equal and bisect each other. The quadrilateral is a :

1. square

2. rhombus

3. parallelogram

4. rectangle

A quadrilateral will be a square, if its:

1. each angle is 90°

2. each angle is 90° and the diagonals are equal

3. all the sides are equal

4. all the sides are equal and each angle is 90°