Trapezoid
From Conservapedia
A trapezoid (British: trapezium) is a four-sided polygon with two parallel sides.
The following properties arise from the definition:
- Two of the pairs of adjacent angles sum to 180o
- The area of the trapezium is the average of the parallel sides multiplied by the distance between them.
- The perimeter is equal to the sum of the oblique sides times the sum of the tangent sides.
- The sum of the oblique angles will be equal to the sum of the tangent angles.
