Circumference of Ellipse
The circumference of an ellipse is calculated by formulas but the formulas are only approximate. In practice you can read different formulas in different books. To calculate the circumference of an ellipse we need to know a length of its semi-major and semi-minor axis. For example, to know the length of an elliptic running track or any playground, you can use this formula. The elementary unit is one metre (1 m).
Circumference of Ellipse - formula
Circumference of Ellipse ≈ π × √2 × ((semi-major length of a)2 + (semi-minor length of b)2)
C ≈ π × √2 × (a2 + b2)