# Hollow Ellipse

Written by Jerry Ratzlaff on . Posted in Plane Geometry

•  Hollow ellipse (a two-dimensional figure) has two ellipses with a conic section or a stretched circle.
• The major axis is always the longest axis in an ellipse.
• The minor axis is always the shortest axis in an ellipse.

## Formulas that use Hollow ellipse Area

 $$\large{ A_{area} = \pi \; \left( a \; b - e \; f \right) }$$

### Where:

$$\large{ A_{area} }$$ = area

$$\large{ a }$$ = length semi-major axis

$$\large{ b }$$ = length semi-minor axis

$$\large{ e }$$ = length inner semi-major axis

$$\large{ f }$$ = length inner semi-minor axis

$$\large{ \pi }$$ = Pi

## Formulas that use Hollow ellipse Inner Semi-major Axis Length

 $$\large{ e = a-g }$$

### Where:

$$\large{ e }$$ = length semi-major axis

$$\large{ b }$$ = length semi-minor axis

$$\large{ g }$$ = ring width

## Formulas that use Hollow ellipse Inner Semi-minor Axis Length

 $$\large{ f = b-g }$$

### Where:

$$\large{ f }$$ = length semi-minor axis

$$\large{ b }$$ = length semi-minor axis

$$\large{ g }$$ = ring width