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Perimeter of a trapezoid ("trapezium" in British usage)
 
Definition: The total distance around the outside of a trapezoid
Try this Drag any orange dot to resize the trapezoid. The perimeter is calculated as you drag.
(If there is no image below, see support page.)

How to find the perimeter of a trapezoid

Like any polygon, the perimeter is the total distance around the outside, which can be found by adding together the length of each side. Or as a formula:

perimeter = a+b+c+d where:
a,b,c,d are the lengths of each side of the trapezoid

In the figure above, drag any orange dot to resize the trapezoid. From the side lengths shown, calculate the perimeter and verify your result matches the formula at the top of the diagram.

Coordinate Geometry

In coordinate geometry, if you know the coordinates of the four vertices, you can calculate various properties of it, including the area and perimeter. For more on this, see Trapezoid area and perimeter (Coordinate Geometry)

Related polygon topics

General

Types of polygon

Area of various polygon types

Perimeter of various polygon types

Angles associated with polygons

Named polygons

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