1. Quadrilateral Scrapbook
WILLIAM.S
MARCH 13, 2011

2. Irregular Quadrilateral
A plane figure bounded by four straight line segments is called an irregular quadrilateral.             The area of any irregular quadrilateral can be calculated by dividing it into triangles.
Example:             Find the area of quadrilateral A,B,C,D whose sides are 9,40,28 and 15m.

3. Parallelogram
a quadrilateral having both pairs of opposite sides parallel to each other.

4. Square
The square is probably the best known of the quadrilaterals. It is defined as having all sides equal, and its interior angles all right angles (90°). From this it follows that the opposite sides are also parallel.

5. Rhombus
A rhombus is a parallelogram its a bit like a that can 'lean over' and the interior angles ARE LESS THAN 90’. Sometimes called a 'diamond' or 'lozenge' shape.

6. Rectangle
The rectangle, like the square, is one of the most commonly known quadrilaterals. It is defined as having all four interior angles 90° (right angles). OPPOSITE SIDES ARE PARALLEL

7. Trapezoid
is a quadrilateral with one pair of opposite sides parallel. It is not a parallelogram because only one pair of sides is parallel. It is called a regular trapezoid if the sides that aren't parallel are equal in length and both angles coming from a parallel side are equal