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Girard's Spherical Excess Formula

Let a Spherical Triangle $\Delta$ have angles $A$, $B$, and $C$. Then the Spherical Excess is given by

\begin{displaymath}
\Delta=A+B+C-\pi.
\end{displaymath}

See also Angular Defect, L'Huilier's Theorem, Spherical Excess


References

Coxeter, H. S. M. Introduction to Geometry, 2nd ed. New York: Wiley, pp. 94-95, 1969.




© 1996-9 Eric W. Weisstein
1999-05-25