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Properties of Trapezoid Calculator

Online trapezoid area calculator. Enter the two bases and height to get (base₁+base₂)×height÷2, with isosceles-trapezoid properties—great for geometry.

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Area=(top+bottom)×height/2
Shorter parallel side
Longer parallel side
Distance between bases

📖 Tutorial | Trapezoid

1. Definition
A trapezoid has one pair of parallel sides (bases); the other sides are legs.
2. Formula & Notation
a, bBases
hHeight
SArea, (a+b)h/2
3. Properties & Laws
  • Area=(a+b)h/2;
  • Isosceles: equal legs;
  • Equal base angles and diagonals;
  • Right trapezoid has a perpendicular leg.
4. Steps
  1. Enter bases a, b and height h;
  2. Click "Calculate";
  3. Or click "Load Example".
5. Worked Examples
Example: bases 4, 8, height 5.
Solution: area = 30.
6. Common Pitfalls
Sum the bases;
Divide by 2;
A parallelogram is not a trapezoid here.

❓ FAQ | Trapezoid

Area?
(a+b)×height/2.
Isosceles properties?
Equal legs, base angles, diagonals.
4,8,5 area?
30.
Right trapezoid?
One leg perpendicular.
Parallelogram a trapezoid?
Not under the exclusive definition.
Height?
Perpendicular distance between bases.