Excess of a triangle
From Encyclopedia of Mathematics
spherical excess, excess
The difference between the sum of the angles of a spherical triangle and two right angles. The excess 
of a spherical triangle is proportional to its area 
: 
, where 
is the radius of the sphere containing the spherical triangle.
Comments
This notion is sometimes called the defect of the triangle (cf. Triangle, defect of a).
References
| [a1] | M. Berger, "Geometry" , II , Springer (1987) pp. 278 |
| [a2] | H.S.M. Coxeter, "Non-Euclidean geometry" , Univ. Toronto Press (1957) |
| [a3] | M. Greenberg, "Euclidean and non-Euclidean geometry" , Freeman (1980) pp. 105 |
How to Cite This Entry:
Excess of a triangle. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Excess_of_a_triangle&oldid=13640
Excess of a triangle. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Excess_of_a_triangle&oldid=13640
This article was adapted from an original article by A.B. Ivanov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article