Trapezoid Side Calculator
Calculate the missing side length of a trapezoid using perimeter and known sides
Calculate Missing Trapezoid Side
Choose which side you want to calculate
Total perimeter of the trapezoid
This side will be calculated
Length of side B
Length of side C
Length of side D
Calculation Results
Enter the perimeter and three known sides to calculate the missing side
Example Calculation
Garden Border Trapezoid
Given: Trapezoid garden border with perimeter = 24 meters
Known sides: A = 6m, B = 8m, C = 4m
Find: Side D
Solution
Side D = Perimeter - (Side A + Side B + Side C)
Side D = 24 - (6 + 8 + 4)
Side D = 24 - 18
Side D = 6 meters
Trapezoid Properties
Parallel Sides
At least one pair of parallel sides (bases)
Four Sides
Total of four sides with varying lengths
Perimeter
Sum of all four side lengths
Calculation Tips
You need exactly 3 known sides and the perimeter
All sides must be positive numbers
The largest side must be less than the sum of the other three
Choose which side you want to calculate from the buttons
Understanding Trapezoid Side Calculations
What is a Trapezoid?
A trapezoid is a quadrilateral (four-sided polygon) with at least one pair of parallel sides. The parallel sides are called bases, and the non-parallel sides are called legs. Different types include isosceles trapezoids (equal legs) and right trapezoids (one right angle).
Finding Missing Sides
- •Identify which side is missing
- •Add the lengths of all known sides
- •Subtract from the total perimeter
- •Verify the result forms a valid trapezoid
Formula
Missing Side = Perimeter - (Sum of other sides)
Side = P - (a + b + c)
- P: Total perimeter of the trapezoid
- a, b, c: Lengths of the three known sides
- Side: The missing fourth side
Note: All measurements must use the same units