How do you find trapezoid area?

Area equals one half the sum of bases times the height.

Can you solve a trapezoid from four sides?

Yes. If dimensions are valid, angles, height, area, and diagonals can be computed using the Law of Cosines.

Angles A and D are base angles on the long base; B and C are on the short base. A + B = 180°, D + C = 180°.

Choose the mode that matches your known values. All angles (A,B,C,D) are included.

Enter known values – missing ones will be calculated

Calculation mode:

Decimal places:

🔹 Four sides (a, b, c, d)

Leg a (left)

Short base b

Leg c (right)

Long base d

🔹 Bases (b, d) + Height h + angle A (degrees)

Short base b

Long base d

Height h

Angle A (°)

* Angle A is the left base angle (between side a and base d).

Reference: sides a (left), b (short top), c (right), d (long base), height h, angle A at left

Leg a--

Short base b--

Leg c--

Long base d--

Height h--

Perimeter--

Area--

Diagonal AC--

Diagonal BD--

Angle A--

Angle B--

Angle C--

Angle D--

Click Calculate to see the detailed steps.