Parallelogram

A parallelogram is a four-sided shape whose opposite sides are parallel. It is, in effect, a rectangle that has been leaned on.^[1]

A parallelogram’s opposite sides never meet. They know they never meet because they are parallel; they know they are parallel because they have never met. Geometers regard this as the most stable relationship in mathematics.

Family

The parallelogram family includes the rectangle, the rhombus and the square, all of which are parallelograms, though only the parallelogram is willing to say so at parties. The square is technically every member of the family at once and is not allowed to fill in forms. The trapezium has only one pair of parallel sides and attends family events as a plus-one.

Area

The area of a parallelogram is its base multiplied by its height, not its slanted side. This single fact has been the downfall of more homework than any other, apart from the dog.^[2]

Drawing

Parallelograms are most often drawn by accident, by people attempting to draw a rectangle on a slope. They are also the shape most commonly produced by anyone trying to straighten a picture frame.

See also

• Rectangle – before the leaning
• Rhombus – a parallelogram with matching sides
• Trapezium – plus-one

References

1. Slant, L. (1988). Leaning Rectangles. Angle Press.
2. Base, H. & Height, H. (2005). “Not the Slanty Bit”. Homework Review 22: 4.
3. Lines, P. (1999). We Never Met. Euclid & Daughters.