Overview
A trapezoid is a quadrilateral with one pair of parallel opposite sides called the bases. Its area is the average of the bases times the height, and its perimeter is the sum of all four sides.
Formula
Area = ((b₁ + b₂) ÷ 2) × h.
How it works
1
Enter both bases
The bases are the two parallel sides.
2
Enter the height
The perpendicular distance between the bases.
3
Compute the average
Add the bases and divide by 2.
4
Multiply by the height
This gives the trapezoid's area.
Worked examples
Example 1: bases 8 and 5, height 4
Area = (13 ÷ 2) × 4 = 26.
Example 2: bases 10 and 6, height 3
Area = (16 ÷ 2) × 3 = 24.
Frequently asked questions
Can a trapezoid have equal bases?
Yes, and then it becomes a parallelogram.
What is the median?
The segment joining the midpoints of the non-parallel sides, with length equal to the average of the bases.
Are there different types of trapezoids?
Yes: right, isosceles and scalene trapezoids.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.