Semi-major and Semi-minor Axis of an Ellipse
The major axis is always the longest axis in an ellipse.- The minor axis is always the shortest axis in an ellipse.
Semi-major and Semi-minor Axis formulas |
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\(\large{ a = \frac{A}{\pi \;b} }\) \(\large{ a = \frac {l} {1\;-\; \epsilon^2} }\) \(\large{ b = \frac{A}{\pi \;a} }\) \(\large{ b = a \sqrt {1 - \epsilon^2} }\) |
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| Symbol | English | Metric |
| \(\large{ a }\) = length semi-major axis | \(\large{ in }\) | \(\large{ mm }\) |
| \(\large{ b }\) = length semi-minor axis | \(\large{ in }\) | \(\large{ mm }\) |
| \(\large{ A }\) = area | \(\large{ in^2 }\) | \(\large{ mm^2 }\) |
| \(\large{ \epsilon }\) (Greek symbol epsilon) = eccentricity | \(\large{ dimensionless }\) | |
| \(\large{ \pi }\) = Pi | \(\large{3.141 592 653 ...}\) | |
| \(\large{ l }\) = semi-latus rectum | \(\large{ in }\) | \(\large{ mm }\) |
Tags: Surveying Equations