Geometry Tool

Trapezoid Calculator - Area of Trapezoid Calculator & Isosceles Trapezoid Calculator

Free trapezoid calculator & area of trapezoid calculator. Calculate isosceles trapezoid area, perimeter, angles, height, sides & diagonals. Our trapezium calculator supports isosceles, right, and general trapezoids with step-by-step analysis and multiple unit systems.

Last updated: October 19, 2025

Multiple trapezoid types and calculation modes
Area, perimeter, median, and diagonal calculations
Geometry formulas with step-by-step analysis

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Trapezoid Calculator
Calculate area, perimeter, and properties of trapezoids

Trapezoid Properties

Area

50.00 cm²

Perimeter

30.77 cm

Median Length

10.00 cm

Diagonal (approx)

11.18 cm

Trapezoid Type:

Isosceles Trapezoid

Formula Used:

A = ½(b₁ + b₂)h, legs = √(h² + ((b₁-b₂)/2)²)

Analysis:

Isosceles trapezoid with equal legs = 5.39 units

Trapezoid Properties:

  • • Has exactly one pair of parallel sides (bases)
  • • Area = ½(b₁ + b₂) × height
  • • Median connects midpoints of legs and equals (b₁ + b₂)/2
  • • Isosceles trapezoids have equal legs and equal base angles

Trapezoid Calculator Types & Features

Isosceles Trapezoid Calculator
Calculate area, perimeter, angles & diagonals for isosceles trapezoids

Equal legs and base angles

Area = ½(b₁ + b₂) × h

Perfect for symmetric designs and architectural applications

Area of Trapezoid Calculator
Find area using bases and height with step-by-step solutions

Universal area formula

A = ½(b₁ + b₂) × h

Works for all trapezoid types: isosceles, right, scalene

Trapezium Calculator
British term for trapezoid - same calculations, different name

UK/International standard

Same as trapezoid

Identical calculations with British terminology

Right Trapezoid Calculator
Calculate properties for trapezoids with one right angle

One perpendicular leg

Simplified calculations

Easier leg length calculations due to right angle

Height of Trapezoid Calculator
Find height when given area and base lengths

Height from area

h = 2A/(b₁ + b₂)

Rearrange area formula to solve for height

Trapezoid Angle Calculator
Calculate interior and exterior angles of trapezoids

Angle relationships

Sum = 360°

Use trigonometry and angle properties for calculations

Quick Example Result

Isosceles trapezoid with bases 8 cm and 12 cm, height 5 cm:

Area

50.0 cm²

Perimeter

30.8 cm

Median

10.0 cm

Leg Length

5.39 cm

How Our Trapezoid Calculator Works

Our trapezoid calculator applies fundamental geometric principles to analyze quadrilaterals with one pair of parallel sides. The calculations use coordinate geometry, trigonometry, and the Pythagorean theorem to determine all trapezoid properties.

Essential Trapezoid Formulas

A = ½(b₁ + b₂) × h (area formula)
P = b₁ + b₂ + l₁ + l₂ (perimeter)
m = (b₁ + b₂)/2 (median length)
l = √(h² + ((b₁-b₂)/2)²) (isosceles legs)

These formulas apply to different trapezoid types. The area formula is universal, while leg calculations depend on whether the trapezoid is isosceles, right, or scalene.

📐 Trapezoid Diagram

Shows parallel bases, height, legs, and median

Geometry Foundation

Trapezoid calculations are based on properties of parallel lines and right triangles. When perpendiculars are dropped from the shorter base to the longer base, they create right triangles that help determine leg lengths. Our calculator handles different trapezoid types with specialized formulas for each configuration.

  • Exactly one pair of parallel sides distinguishes trapezoids from other quadrilaterals
  • The median (midsegment) is always parallel to bases and equals their average
  • Isosceles trapezoids have equal legs and base angles
  • Right trapezoids have one perpendicular leg simplifying calculations
  • Area depends only on bases and height, not leg lengths
  • Diagonal properties vary by trapezoid type

Sources & References

  • Geometry - Jurgensen, Brown, Jurgensen (McDougal Littell)Standard high school geometry textbook covering quadrilaterals
  • Elementary Geometry for College Students - Alexander, Koeberlein (6th Edition)College-level geometry with trapezoid properties and proofs
  • Mathematical Handbook - CRC Press Standard Mathematical TablesReference for geometric formulas and calculations

Exploring more geometry? Try our free fall calculator for physics and partial pressure calculator for chemistry.

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Trapezoid Calculator Examples

Isosceles Trapezoid Calculator Example
Calculate area, perimeter, and properties for an isosceles trapezoid with specific dimensions

Given Dimensions:

  • Base 1 (top): 6 meters
  • Base 2 (bottom): 10 meters
  • Height: 8 meters
  • Type: Isosceles trapezoid

Calculation Steps:

  1. Apply area formula: A = ½(b₁ + b₂) × h
  2. A = ½(6 + 10) × 8 = ½(16) × 8 = 64 m²
  3. Calculate legs: l = √(8² + 2²) = √68 = 8.25 m
  4. Perimeter: P = 6 + 10 + 2(8.25) = 32.5 m

Result: Area = 64 m², Perimeter = 32.5 m, Leg length = 8.25 m

Perfect for architectural designs and engineering applications!

Right Trapezoid Example

Bases: 5m & 8m, Height: 6m

Area = 39 m², Perimeter = 25.6 m

Trapezium Calculator Example

Bases: 4m & 7m, Height: 5m

Area = 27.5 m², Perimeter = 19.6 m

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