Lesson 4: Area of Trapezoids

Property

• A trapezoid is a four-sided figure, a quadrilateral, with two sides that are parallel and two sides that are not. The parallel sides are called the bases.
• The area $A$ of a trapezoid with parallel bases $b_1$ and $b_2$ and perpendicular height $h$ is given by the formula:

Examples

• A trapezoid has a height of 8 inches and bases of 10 inches and 15 inches. The area is $A = \frac{1}{2} \cdot 8 \cdot (10 + 15) = 4 \cdot 25 = 100$ square inches.

• Find the area of a trapezoid with a height of 4 feet and bases of 7.5 feet and 11.5 feet. The area is $A = \frac{1}{2} \cdot 4 \cdot (7.5 + 11.5) = 2 \cdot 19 = 38$ square feet.

Property

To find the area of a trapezoid described in a real-world context, use the area formula:

Examples