What Is a Parallelogram? (Mathematics Lesson)
What Is a ParallelogramA paralleogram is a four sided shape with opposite sides parallel and equal in length.
Properties of Parallelograms
- Opposite sides of a parallelogram are parallel.
- Opposite sides of a parallelogram are of equal length.
- Opposite angles of a parallelogram are equal.
- Adjacent angles of a parallelogram add up to 180°. They are supplementary angles.
- All angles of a parallelogram add up to 360°.
- The diagonals of a parallelogram bisect each other. The diagonals cross each other half-way along their lengths.
The Perimeter of a ParallelogramThe perimeter of a parallelogram is given by the formula:
where of b is the length of the base and s is the length of the side of the parallelogram.
The Area of a ParallelogramThe area of a parallelogram is given by the formula:
where b is the length of the base and h is the height of the parallelogram.
NoteWHAT'S IN A NAME?
Parallelogram comes from the Greek word 'parallelogrammon' meaning 'parallel sides'.
A PARALLELOGRAM IS A POLYGONA parallelogram is a type of polygon.
A polygon is a 2-dimensional shape with straight sides.
A parallelogram is an irregular polygon. Irregular polygons have different length sides and different angles.
A PARALLELOGRAM IS A QUADRILATERALA parallelogram is a quadrilateral.
A quadrilateral is a four-sided polygon.
Squares, rectangles and trapezoids are also quadrilaterals.
INTERIOR ANGLES OF A PARALLELOGRAMA parallelogram is a four-sided polygon. The sum of the interior angles of an n-sided polygon is is: (n - 2) × 180°
This means the interior angles of a polygon add up to:
(4 - 2) × 180° = 360°
This is the case for all quadrilaterals, such as squares, rectangles and trapezoids.