Trapezoid Calculator

Calculate area, perimeter, height, and angles of trapezoids with step-by-step solutions

Trapezoid Calculator

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units
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Perpendicular distance between the parallel bases

Trapezoid Diagram

b = ?a = ?c = ?d = ?h = ?

Calculation Results

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Area (units²)
0
Median

Area Formula: A = (a + b) × h / 2

Calculation: A = (0 + 0) × 0 / 2 = 0 units²

Median: m = (a + b) / 2 = (0 + 0) / 2 = 0 units

⚠️ Please enter valid positive values for all required fields

Trapezoid Properties

• A trapezoid has exactly one pair of parallel sides (the bases)
• The sum of all interior angles equals 360°
• Adjacent angles along each leg are supplementary (sum to 180°)
• The median connects the midpoints of the legs and equals (a + b) / 2

Example Calculation

Right Trapezoid Example

Bottom base (a): 8 units

Top base (b): 5 units

Height (h): 3 units

Left leg (c): 3 units (perpendicular to bases)

Right leg (d): 5 units

Calculations

Area: A = (8 + 5) × 3 / 2 = 19.5 units²

Perimeter: P = 8 + 5 + 3 + 5 = 21 units

Median: m = (8 + 5) / 2 = 6.5 units

Type: Right trapezoid (has a 90° angle)

Types of Trapezoids

1

Scalene Trapezoid

All sides have different lengths

2

Isosceles Trapezoid

Both legs have equal length

3

Right Trapezoid

Has at least one 90° angle

Formula Reference

Area

A = (a + b) × h / 2

Perimeter

P = a + b + c + d

Median

m = (a + b) / 2

Height from Area

h = 2A / (a + b)

Height from Trigonometry

h = c × sin(α)

Understanding Trapezoids

What is a Trapezoid?

A trapezoid (or trapezium in British English) is a quadrilateral with exactly one pair of parallel sides called bases. The non-parallel sides are called legs. The distance between the parallel sides is the height.

Key Properties

  • Exactly one pair of parallel sides (bases)
  • Sum of interior angles equals 360°
  • Adjacent angles are supplementary
  • Median is parallel to bases

Applications

  • Architecture and construction
  • Engineering and design
  • Land surveying and area calculation
  • Mathematical modeling

Note: A rectangle is a special case of trapezoid where both pairs of opposite sides are parallel. All rectangles are trapezoids, but not all trapezoids are rectangles.