Area of Trapezoids Worksheets
Free printable area of trapezoids worksheets. Use both parallel sides and the height, ½ × (a + b) × h. Drawn to scale, answers in cm², with a key.
Each question draws a trapezoid with its two parallel sides and its height labelled, and asks for the area. Add the parallel sides, multiply by the height, and halve: sides of 7 cm and 3 cm with a height of 5 cm make ½ × (7 + 3) × 5 = 25 cm².
The longer parallel side is always the base, along the bottom, and the shorter one runs across the top. Both slanted sides lean in, and neither is labelled. Every length is 2 cm to 12 cm, and the shapes are chosen so that every area is a whole number of cm².
What this worksheet covers
- Find the area of a trapezoid from its parallel sides and its height
- Use the formula A = ½(a + b)h
Common Core standards
- 6.G.A.1 Find the area of right triangles, special quadrilaterals and other polygons by composing them into rectangles or decomposing them into triangles and other shapes.
Frequently asked questions
Why does the trapezoid formula add the two sides?
Two copies of the same trapezoid, one turned upside down, fit together into a parallelogram. Its base is the two parallel sides added together and its height is the same, so one trapezoid is half of it: sides of 9 cm and 5 cm with a height of 4 cm make ½ × 14 × 4 = 28 cm².
Which sides are a and b?
The two parallel sides: the base along the bottom and the shorter side across the top. The slanted sides are not part of the formula, which is why these sheets leave them unlabelled.
Can I halve first?
Yes, whichever is easiest: halve the sum, halve the height, or halve at the end. For ½ × (7 + 3) × 5, that is 5 × 5 or half of 50, and both give 25 cm².
What grade is the area of a trapezoid?
Sixth grade. It is usually the last of the area formulas built from the rectangle, after the parallelogram and the triangle, because it uses both of them.