How to Calculate Irregular Polygon
What is Irregular Polygon?
Calculates irregular polygon area using coordinate vertices. Handles non-regular multi-sided shapes.
Formula
Shoelace formula: A = |Σ(x_i × y_(i+1) - x_(i+1) × y_i)| / 2
- A
- |Σ(x_i × y_(i+1) - x_(i+1) × y_i)| / 2 — |Σ(x_i × y_(i+1) - x_(i+1) × y_i)| / 2
Step-by-Step Guide
- 1Shoelace formula: A = |Σ(x_i × y_(i+1) - x_(i+1) × y_i)| / 2
- 2Order vertices clockwise or counter-clockwise consistently
- 3Close polygon by including first vertex at end
- 4Works for any polygon (convex or concave)
Worked Examples
Input
Coords x,y list
Result
Shoelace formula
Common Mistakes to Avoid
- ✕Inconsistent vertex ordering
- ✕Forgetting to close polygon (include first vertex again at end)
Frequently Asked Questions
What's the Shoelace formula?
Calculates area from vertex coordinates; works for any polygon shape.
Does order of vertices matter?
Yes; consistent clockwise or counter-clockwise required; opposite order gives negative area.
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