From Wikibooks, open books for an open world < Geometry Jump to:
navigation, search  A Trapezoid (American English) or Trapezium
(British English) is a quadrilateral that has two parallel sides
and two non parallel sides.  Some properties of trapezoids:    •
The interior angles sum to 360° as in any quadrilateral.   • The
parallel sides are unequal.   • Each of the parallel sides is
called a base (b) of the trapezoid. The two angles that join one
base are called 'base angles'.   • If the two non-parallel sides
are equal, the trapezoid is called an isosceles trapezoid.     •
In an isosceles trapezoid, each pair of base angles are equal.
• A line segment connecting the midpoints of the non-parallel
sides is called the median (m) of the trapeziod.     • The
median of a trapezoid is equal to one half the sum of the bases
(called b1 and b2).   • A line segment perpendicular to the
bases is called an altitude (h) of the trapezoid.  The area (A)
of a trapezoid is equal to the product of an altitude and the
median.