The Ellipse Horizontal Chord from Center calculator computes the chord of an ellipse where the chord is horizontal at a distance from the semi-major axis.
INSTRUCTIONS: Choose units and enter the following:
- (A) Semi-Major Axis
- (B) Semi-Minor Axis
- (d) Vertical Distance from Major Axis
Ellipse Horizontal Chord from Center (HC): The results are returned in centimeters. However, these can be automatically converted to compatible units via the pull-down menu.
The Math / Science
The Ellipse Horizontal Chord from Center equation computes the length of the horizontal chord in an ellipse that is a distance from the semi-major axis.
`HC = 2*(A/B) * sqrt(B*B-d*d)`
where:
- HC = length of the horizontal chord
- A = length of semi-major axis
- B = length of semi-minor axis
- d = vertical distance from the major axis.
An ellipse is defined by the semi-major axis (A) and semi-minor axis (B).
- Area of Ellipse: Computes the area of an ellipse based on the semi-major axis (a) and the semi-minor axis (b).
- Rumanujan's Circumference of an Ellipse 1 : The first of two of Rumanujan's approximations of the circumference (perimeter) of an ellipse based on the semi-major axis (a) and the semi-minor axis (b).
- Rumanujan's Circumference of an Ellipse 2: The second Rumanujan approximations of the circumference (perimeter) of an ellipse based on the semi-major axis (a) and the semi-minor axis (b).
- Circumference of an Ellipse (other) Another common estimation of the circumference (perimeter) of an ellipse based on the semi-major axis (a) and the semi-minor axis (b).
- Ellipse Axis Length: Approximates one axis of an ellipse bases on the circumference and the other axis.
- Eccentricity of an Ellipse
Computes the eccentricity of an ellipse which is based on the ratios of the semi-major axis (a) and the semi-minor axis (b).
- Linear Eccentricity of an Ellipse (f) Computes the distance from the center to either foci (f), which is the linear eccentricity of an ellipse. This is based on the semi-major axis (a) and the semi-minor axis (b).
- Mean Radius of an Ellipse Computes the mean radius of an ellipse. This would define a circle with the same approximate area, based on the ellipse's semi-major axis (a) and the semi-minor axis (b).
- Elliptical Volume Computes the volume of a column with an elliptical base.

Ellipse Chords
Ellipsoid (3D Elliptical Shape)
- Ellipsoid - Volume computes the volume of an ellipsoid based on the length of the three semi-axes (a, b, c)

- Ellipsoid - Surface Area computes the surface area of an ellipsoid based on the length of the three semi-axes (a, b, c)
- Ellipsoid - Mass or Weight computes the mass or weight of an ellipsoid based on the length of the three semi-axes (a, b, c) and the mean density.
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