A parallelogram is a quadrilateral in which both pairs of opposite sides are parallel.
In the figure, ABCD is a parallelogram as AB || CD (or AB parallel to CD) and AD || BC (or AD parallel to BC).
It is denoted by ||gm ABCD.
Properties of parallelogram
1. The opposite sides of a parallelogram are equal.
In the figure, ABCD is a parallelogram, where
AB = CD and BC = AD
2. The opposite angles of a parallelogram are equal.
In the figure,
A = C and
B = D.
3. Diagonals of a parallelogram bisect each other.
We will observe that in case OA – OC and OB – OD are either zero or so small that the same may be ignored.
Thus, in each case, OA = OC and OB = OD.
Types of a parallelogram
Some special types of a parallelograms are:
A rectangle is a parallelogram one of whose angles is a right angle.
In the adjoining figure, ABCD is a rectangle in which B = 90°
A square is a rectangle in which all sides are equal.
In given figure, ABCD is a square as
AB = BC = CD = DA and B = 90°
Rhombus is a parallelogram whose all sides are equal.
In given below figure, ABCD is a rhombus as
AB = BC = CD = DA