# Foci of an Ellipse

on . Posted in Plane Geometry

Foci is a point used to define the conic section.  F and G seperately are called "focus", both togeather are called "foci".

## Foci of an Ellipse formula

$$\large{ c^2 = a^2 - b^2 }$$
Symbol English Metric
$$\large{ c }$$ = length center to focus $$\large{ in }$$  $$\large{ in }$$
$$\large{ a }$$ = length semi-major axis $$\large{ in }$$ $$\large{ in }$$
$$\large{ b }$$ = length semi-minor axis $$\large{ in }$$ $$\large{ in }$$
$$\large{ F }$$ and $$\large{ G }$$ = focus $$\large{ in }$$ $$\large{ in }$$