Horn angle

In mathematics, a horn angle, also called a cornicular angle, is a type of curvilinear angle defined as the angle formed between a circle and a straight line tangent to it, or, more generally, the angle formed between two curves at a point where they are tangent to each other.

See also

History of geometry
Non-Archimedean geometry

References

Thomas Little Heath, T.L. (1908). The thirteen books of Euclid's Elements 2. The University Press. pp. 39–42.

External links

Weisstein, Eric W., "Horn Angle", MathWorld.
David E. Joyce, "Definition 8" Euclid's Elements Book I
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Mathematics Encyclopedia