Quadrilateral

Six different types of quadrilaterals

Edges and Vertices

4

In Euclidean plane
geometry, a quadrilateral is a polygon with four sides (or 'edges') and four vertices or corners.
Sometimes, the term quadrangle is
used, by analogy with triangle,
and sometimes tetragon for consistency with pentagon (5sided), hexagon (6sided) and so on. The word quadrilateral is made of the words quad (meaning "four") and lateral (meaning "of sides").
Quadrilaterals are simple (not selfintersecting) or complex (selfintersecting), also called
crossed. Simple quadrilaterals are either convex or concave.
The interior angles of a simple quadrilateral add up to
360 degrees of arc.
http://en.wikipedia.org/wiki/Quadrilateral
The above explanation is copied from
Wikipedia, the free encyclopedia and is remixed as
allowed under the Creative Commons Attribution ShareAlike
3.0 Unported License.
(Our solved example in mathguru.com also uses the below concept.
This is our own explanation, it is not taken from Wikipedia.)
To construct a quadrilateral
when 2 adjacent sides( x units, y units) and 3 angles(say 105, 105, 60) are
known
• Draw a line segment MO = x units
• Make an angle of 105at O
• With O as the centre and radius y units, we mark an arc on the
ray OX
• Make an angle of 105at R
• Make an angle of 60at M
• Mark the point of intersection at R
• MORE is the required Quadrilateral