Ellipse Area
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Constant used — built into this formula, no need to enter
Pi · exactLearning zone
An ellipse is a circle stretched by different amounts in two perpendicular directions, and its area follows suit: where the circle has πr², the ellipse replaces r² with the product of its two semi-axes, giving A = πab with π ≈ 3.14159265. Set a = b = r and the circle formula reappears exactly. Curiously, while the ellipse's area is this simple, its perimeter has no elementary closed form at all.
Ellipse Area
Where
- = Area
- = Semi-major axis
- = Semi-minor axis
Missing one of these? Work it out first, then come back
- Area — Area of a Circle, Area of a Triangle
- Semi-major axis — Kepler's Third Law (Ratio Form), Area Moment of Inertia — Rectangle
- Semi-minor axis — Area Moment of Inertia — Rectangle, Pythagorean Theorem