peterpong wrote:I'm not a native speaker, so I'm not sure if there is a difference in the meaning of these two words. In german a rectangle has four right angles, and is a special form of a quadrilateral.
Is it like this in american englisch ? Or is it possible that a rectangle is a parallelogramm or even a geometric figure without any similiar angles or sides ?
Any four-sided shape is a Quadrilateral. But the sides have to be straight, and it has to be 2-dimensional.
A rectangle is a four-sided shape where every angle is a right angle (90°). Also opposite sides are parallel and of equal length.
A square has equal sides and every angle is a right angle (90°). Also opposite sides are parallel. A square also fits the definition of a rectangle (all angles are 90°), and a rhombus (all sides are equal length).
A rhombus is a four-sided shape where all sides have equal length. Also opposite sides are parallel and opposite angles are equal. The diagonals of a rhombus bisect each other at right angles.
A parallelogram's opposite sides are parallel and equal in length. Also opposite angles are equal.
NOTE: Squares, Rectangles and Rhombuses are all Parallelograms.
