Note: This site uses the inclusive definition of trapezoid.

Quadrilateral Family

A quadrilateral is ANY four-sided figure. Do not assume any additional properties unless you are given additional information.

In a kite, the congruent sides are adjacent (or consecutive) and not opposite one another. (Kites referred to on this site are convex kites.)

This site uses the definition that a trapezoid has "at least" one pair of parallel sides. Use the definition stated by your teacher.

Be sure that you are given (or can prove) that a trapezoid is isosceles. Never "assume" it is isosceles by looking at the diagram.

Notice that these properties of a parallelogram come in sets of twos: 2 about sides, 2 about angles, and 2 about diagonals.

Notice that you only need to add two additional properties to a parallelogram
to describe a rectangle.

Notice that adding 3 additional properties to a parallelogram will describe a rhombus. A rhombus is a slanted square.

The square is the most specific member of the quadrilateral family. It has the largest number of properties.

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