Segments of these three circles form a spherical triangle on the sphere. In this cut and folded tan paper model, Wheeler labels the vertices of this triangle ABC. Consider a point (not named by ...

Learn about angles in triangles and quadrilaterals with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

Ivo G. Rosenberg, Frank Stenger, A Lower Bound on the Angles of Triangles Constructed by Bisecting the Longest Side, Mathematics of Computation, Vol. 29, No. 130 (Apr., 1975), pp. 390-395 ...