If the diagonals of a square ABCD intersect each other at point O, the triangle OAB is :

1. an equilateral triangle.

2. a right-angled but not an isosceles triangle.

3. an isosceles but not a right-angled triangle.

4. an isosceles right-angled triangle.

A quadrilateral in which the diagonals are equal and bisect each other at right angles is a :

1. rectangle which is not a square.

2. rhombus which is not a square.

3. square.

4. kite which is not a square.

If the diagonals of a quadrilateral bisect each other at right angle, the quadrilateral is :

1. square

2. rhombus

3. parallelogram

4. rectangle

State, 'true' or 'false' :

(i) The diagonals of a rectangle bisect each other.

(ii) The diagonals of a quadrilateral bisect each other.

(iii) The diagonals of a parallelogram bisect each other at right angle.

(iv) Each diagonal of a rhombus bisects it.

(v) The quadrilateral, whose four sides are equal, is a square.

(vi) Every rhombus is a parallelogram.

(vii) Every parallelogram is a rhombus.

(viii) Diagonals of a rhombus are equal.

(ix) If two adjacent sides of a parallelogram are equal, it is a rhombus.

(x) If the diagonals of a quadrilateral bisect each other at right angle, the quadrilateral is a square.