What are quadilaterals?
A quadrilateral is a polygon with
four sides (or 'edges') and four
vertices or corners.
In geometry a polygon is traditionally a
plane figure that is bounded by a closed
path or circuit, composed of a finite
sequence of straight line segments (i.e., by
a closed polygonal chain ). These segments
are called its edges or sides, and the
points where two edges meet are the
polygon's vertices (singular: vertex) or
HOW IS A
A quadrilateral is a polygon. In fact
it is a 4-sided polygon, just like a
triangle is a 3-sided polygon, a
pentagon is a 5-sided polygon, and so
A line segment drawn from one vertex of a
quadrilateral to the opposite vertex is
called a diagonal of the quadrilateral. AC
is a diagonal of quadrilateral ABCD, as is
There are seven types of quadrilaterals
that can be divided into two groups:
parallelograms and other quadrilaterals.
parallelograms if both pairs of
opposite sides are equal and parallel
to each other.
• OTHER QUADRILATERALSOther quadrilaterals include
trapeziums, kites and irregular
An irregular quadrilateral does not
have any special properties.
When two sides cross over, you call it
a "Complex" or "Self-Intersecting"
quadrilateral like these:
They still have 4 sides, but two sides cross over.
ANGLE SUM OF A
Draw a quadrilateral ABCD. Then
draw the diagonal AC to form two
FINDING THE FOURTH
ANGLE OF A
If the measurements of three angles
of a quadrilateral are known, then
the missing angle can be calculated
ExampleFind the value of the pronumeral x in the
accompanying diagram. Give reasons for