Back to the index. Or to the chambers
This article has 17 links. View as Cloud or List.
Loading ...
Planetmath Browser (2008—2009)
BSD licence | A django site
All articles taken from PlanetMath.org snapshot under CC-BY-SA licence.
→ The original article on PlanetMath.org
Other Formats: LaTeX
Parallelogram
A parallelogram is a quadrilateral whose opposite sides are parallel.
Some special parallelograms have their own names: squares, rectangles, rhombuses.
A rectangle is a parallelogram whose all angles
are equal (i.e. 
), a rhombus
is a parallelogram whose all sides
are equal, and a square is a parallelogram that is a rectangle and a rhombus at the same time.
Every parallelogram have their opposite sides and opposite
angles equal. Also, adjacent
angles of a parallelogram always add up to 
, and the diagonals
bisect each other.
A base of a parallelogram is one of its sides. Any side of a
parallelogram can be selected as its base. Once a base has been
selected, the height of the parallelogram is defined to be the
length
of any line segment
perpendicular
to the base which extends
from the base to the opposite side parallel to the base. The area
of
a parallelogram with base length 
and height 
is given by the
formula
.
There is also a neat relation between the length of the sides and the lengths of the diagonals called the parallelogram law.