# How to Find the Area of a Trapezoid

## Finding the Area of a Trapezoid

The area of a trapezoid is found using 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. The image below shows what we mean by the lengths of the bases and the height:

## Interactive Widget

Use this interactive widget to create a trapezoid and then calculate its area. Start by clicking in the shaded area.

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Turn your phone on its side to use this widget.

## How to Find the Area of a Trapezoid

Finding the area of a trapezoid is easy.

### Question

What is the area of a trapezoid with bases of length 3 cm and 5 cm and a height of 2 cm, as shown below?

# 1

Area = ½(b1 + b2)h

Don't forget: ½(b1 + b2)h = ½ × (b1 + b2) × h

# 2

Substitute the length of the bases and the height into the formula. In our example, b1 = 3, b2 = 5 and h = 3.

Area = ½ × (3 + 5) × 2

Area = ½ × (8) × 2

Area = 8 cm2

Don't forget: Calculate what's in the brackets () first (using the order of operations). In our example, (3 + 5) = 8.

or: ½ × a number = 0.5 × a number = a number ÷ 2.