Enter the distance from the center to the focus and the distance from the center to the vertex to determine the eccentricity of an ellipse.

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- Sector Area Formula
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## Eccentricity Formula

The following formula is used to calculate the eccentricity of a shape.

e = c / a

- Where e is the eccentricity
- c is the distance from the center to the focus point
- a is the distance from the center to the vertex

## Eccentricity Definition

Eccentricity is defined as the ratio of the distance from the center to a focus point to the distance from the center to the vertex.

## Eccentricity Example

How to calculate eccentricity?

**First, measure the distance c.**C is the measure of the distance from the center of the ellipse to the focus point.

**Next, measure the distance a.**A is the measure of the distance between the center to the vertex.

**Finally, calculate the eccentricity.**Divide the value c by the value a to calculate the eccentricity of the shape.

## FAQ

**What is eccentricity?**

Eccentricity is a measure of the ratio of the locus of a point focus and the distance on the line to that point. In other words, it’s a measure of how much a particular shape, typically an ellipse, varies from a perfect circle. The greater the eccentricity the greater the variation and more oval shape it is.