Geometric plane figures with several sides and a number of equal angles.
Quadrilateral with two sides (bases) that are parallel. It is isosceles when it has two sides that are equal and not parallel, and rectangle when two of its sides form a right angle.
Quadrilateral whose opposite sides are equal in length; the sides meet at right angles.
Equilateral rectangle with four right angles.
Three-sided polygon; triangles are scalene (no side is equal to any other) isosceles (two sides equal) or equilateral (all sides equal).