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- Find the most distant point belong to the Start facet from line between Star and Table facets. Call it "A".
- Find the most distant point from this line on the girdle (in the same half-plane). Call it "B"
- StarUpperRatio is A\/B.
This most consistent case for this algorithm is "F:E" shown on picture above. Please pay attention that segments measured above do not belong to the same line in all cases.