Area of a Trapezoid: Formula, Steps & Examples

The area of a trapezoid is A = ½ × (a + b) × h — half the sum of the two parallel sides (a and b) multiplied by the height (h). A trapezoid is a quadrilateral with exactly one pair of parallel sides. This formula is taught from grades 4–6 in primary school and revisited in middle school. This short guide is for primary and middle school students and parents helping at home.

How to Calculate the Area of a Trapezoid + Example

Use the formula:

Where: a and b = the lengths of the two parallel sides, h = the height (the perpendicular distance between the parallel sides).

Example: A trapezoid has parallel sides a = 8 cm and b = 12 cm, with height h = 6 cm. What is its area?

• Step 1 — add the parallel sides: 8 + 12 = 20
• Step 2 — multiply by the height: 20 × 6 = 120
• Step 3 — divide by two: 120 ÷ 2 = 60

✅ Area = 60 cm²

Why This Formula Matters

Trapezoids are all around us: rooftops, bags, embankments and plots of land. Mastering the area of a trapezoid trains children to break a complex shape into simpler parts — a core geometry skill also used for the area of a parallelogram and the area of a triangle. It appears often in school and national assessment problems.

Other Math Topics

• Area of a Rectangle
• Area of a Parallelogram
• Area of a Triangle
• The Pythagorean Theorem

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