Trapezoid Calculator
Calculate trapezoid area from parallel sides and height, with perimeter when leg lengths are known.
Trapezoid Calculator
Calculate trapezoid area from parallel sides and height, with perimeter when leg lengths are known.
How to use the Trapezoid Calculator
- Enter parallel side A.
- Enter parallel side B.
- Enter the height.
- Optionally enter leg lengths for perimeter.
- Click Calculate.
Formula
Area = (A + B) / 2 × h
Perimeter = A + B + leg1 + leg2
Example
Sides 8 and 12, height 5: Area = (8+12)/2 × 5 = 50.
Step-by-step calculation
- Add parallel sides: 8 + 12 = 20.
- Average: 20 / 2 = 10.
- Multiply by height: 10 × 5 = 50.
- Area = 50 square units.
Real-world uses
- Irrigation channel design.
- Architectural features.
- Road cross-section calculations.
Common mistakes
- Using the non-parallel sides instead of the height.
- Confusing the two parallel sides with the legs.
- Forgetting that height must be perpendicular to the bases.
Frequently asked questions
What is a trapezoid?
A four-sided shape with at least one pair of parallel sides (called bases).
What is the height?
The perpendicular distance between the two parallel sides, not the length of the slanted sides.
Can I find the leg lengths from the area?
Not uniquely. You need additional information like angles or the height and offset.