# rectangle

A rectangle is a quadrilateral whose interior angles are all 90°. If all of its sides are the same length, it is a square. A rectangle is a special case of a parallelogram.

An oblong is alternate name for any rectangle that
is not a square. The word comes from the Latin *ob* ("excessive")
and *longus* ("long"). See also oblong
number.

The smallest square that can be cut into *m* × *n* rectangles,
such that all *m* and *n* are different integers, is the 11 ×
11 square, and the tiling uses five
rectangles. The smallest rectangle that can be cut into *m* × *n* rectangles, such that all *m* and *n* are different integers,
is the 9 × 13 rectangle, and this tiling also uses five rectangles.