The quadrilateral family tree
There’s one key thing that the shapes in this chapter all have in
common—they all have four sides.
Any shape that has four straight sides is a quadrilateral.
Parallelograms, kites, and trapezoids are all part of the
quadrilateral family, along with shapes such as squares and
rectangles. Here’s the quadrilateral family tree so you
can see how they’re all related.
The arrows show you the
The thick arrows on the family
tree show you the relationships
between the shapes. Any shape
at the end of an arrow is a more
specialized form of the shape that
the arrow is coming from. So a
kite is a type of quadrilateral since
it shares the same properties as
a quadrilateral—it has four sides,
with two pairs of separate adjacent
sides. Similarly, a square is type of
rhombus, which means it is also a
type of kite.
The family tree also shows you
which shapes are not directly related.
That means a kite is not a type of
parallelogram and a rectangle is
not a type of trapezoid.
s of congruent sides.
A rhombus has f
congruent sides, but no
Four congruent sides,
e right angles.
his arrow means
te is a
A rhombus is both a typ
e of kite and a typ
llelogram. It has the prop
268 Chapter 6