How to Determine the Area of a Trapezoid
A trapezoid is a four-sided figure with one pair of parallel sides. Because a trapezoid can be dissected into a rectangle and two identical triangles, find it’s area is easy.
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You Will Need
- The dimensions of the trapezoid
- A calculator
Steps
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Step 1
Sum the length of the two parallel sides
Add the lengths of the two parallel sides of the trapezoid.
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Step 2
Multiply by the height
Find the height of the trapezoid. Using a calculator, multiply the sum of the lengths by the height.
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Step 3
Divide by two
Divide the product by two. This is the area of the trapezoid.
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For example, if the height of a trapezoid is 20 inches and two parallel sides of the trapezoid measure 13 and 15 inches, the area is given by = ½ × 20 × (13 + 15), or 280 square inches.
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Step 4
Look for similar examples
Be on the lookout for other polygons whose areas can be determined more easily if the polygons are composed of simpler shapes.
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The word trapezoid comes from the Greek word for table.
