Parallelogram

Parallelogram
This parallelogram is a rhomboid as it has no right angles and unequal sides.
Type	quadrilateral, trapezium
Edges and vertices	4
Symmetry group	C2, [2]+,
Area	b × h (base × height); ab sin θ (product of adjacent sides and sine of the vertex angle determined by them)
Properties	convex

A parallelogram is a polygon with four sides (a quadrilateral). It has two pairs of parallel sides (line segments which never meet if the lines were allowed to extend beyond their end points). The opposite sides of a parallelogram have the same length (they are equally long). The word "parallelogram" comes from the Greek word "parallelogrammon" (bounded by parallel lines).^[1] Rectangles, rhombuses, and squares are all parallelograms.

As shown in the picture on the right, because triangles ABE and CDE are congruent (have the same shape and size),

${\displaystyle AE=CE}$

${\displaystyle BE=DE.}$

In all Parallelogram's opposite angles are equal to each other. Angles which are not opposite in the Parallelogram will add up to 180 degrees.

1. ↑ "Online Etymology Dictionary". etymonline.com. Retrieved 10 January 2011.