The Lesson
A trapezoid is a four sided shape with one pair of opposite parallel sides.
The Oxford English Dictionary defines a rectangle as "a quadrilateral figure having only two sides parallel."
Parts of a Trapezoid
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The parallel sides of a trapezoid are called bases.
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The other sides of a trapezoid are called legs or lateral sides.
Properties of Trapezoids
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Only one pair of sides of a trapezoid is parallel.
The other pair of sides is not parallel.
The Perimeter of a Trapezoid
The perimeter of a trapezoid is given by the formula:

In this formula,
b1 and
b2 are the lengths of the bases of the trapezoid and
l1 and
l2 are the lengths of the legs of the trapezoid.
The Area of a Trapezoid
The
area of a trapezoid is given by the formula:

In this formula,
b1 and
b2 are the lengths of the bases of the trapezoid and h is the height of the trapezoid.
Read more about how to find the area of a trapezoid
Interactive Widget
Here is an
interactive widget to help you learn about trapezoids.
Trapezoid, Trapezium
The shape is called a trapezoid in North America.
In English speaking countries outside North America, a trapezoid is called a trapezium.
What's in a Name?
Trapezoid and trapezium come from the Greek word "trapezion" meaning 'little table'.
A Trapezoid is a Polygon
A trapezoid is a type of
polygon.
A polygon is a 2-dimensional shape with straight sides.
A trapezoid is an irregular polygon. Irregular polygons have different length sides and different angles.
A Trapezoid is a Quadrilateral
A trapezoid is a quadrilateral.
A trapezoid is a four-sided polygon.
Parallelograms,
rectangles and
squares are also quadrilaterals.