A quadrilateral is parallelogram if its opposite angles are equal.

A quadrilateral is a parallelogram if its opposite sides are equal.

A quadrilateral is a parallelogram, if its one pair of opposite sides are equal and parallel.

State the converse and contrapositive of the following statement: If a quadrilateral is a parallelogram then its diagonals bisect each other.

Prove that In a parallelogram, opposite side are equal

Is the following statement true? Why? "Two quadrilaterals are similar, if their corresponding angles are equal".

One angle of a quadrilateral is 180^0 and the remaining three angles are equal. Find the three equal angles.

One angle of a quadrilateral is 180^@ and the remaining three angles are equal. Find the measure of other three equal angles.

Which of the following is not true for a parallelogram ? a) Opposite sides are equal b) Opposite angles are equal c) Opposite angles are bisected by the diagonals d) Diagonals bisect each other

The given figure shows a rectangle ABDC and a parallelogram ABEF, drawn on opposite sides of AB. Prove that : (i) quadrilateral CDEF is a parallelogram, (ii) Area of quad. CDEF = Area of rec. ABDC + "Area of" ////gm.ABEF .

Which of the following statements are true (T) and which are false (F)? (i) In a parallelogram, the diagonals are equal. (ii) In a parallelogram, the diagonals bisect each other. (iii) In a parallelogram, the diagonals intersect each other at right angles. (iv) In any quadrilateral, if a pair of opposite sides is equal, it is a parallelogram. (v) If all the angles of a quadrilateral are equal, it is a parallelogram. (vi) If three sides of a quadrilateral are equal , it is a parallelogram. (vii) If three angles of a quadrilateral are equal, it is a parallelogram. (viii) If all the sides of a quadrilateral are equal it is a parallelogram