Elliptic geometry geometry is that the sum of the interior angles of a triangle is greater than 180 degrees. In the spherical model, for example, a triangle can be constructed with vertices at the locations where the three positive Cartesian coordinate axes intersect the sphere, and all three of its internal angles are 90 degrees, summing to 270 degrees. For sufficiently small triangles, the excess over 180 degrees can be made arbitrarily small. The Pythagorean theorem fails in elliptic geometry. In the 90°–90°–90° triangle described above, all three sides have the same length, and consequently do not satisfy formula_1. The Pythagorean result
Olympic triangle to re-align the course to the new wind direction. With a 60, 60, 60 triangle, if the wind shifts 15 degrees either way, one of the reaching legs will be a 45-degree broad reach, while the other will be at 75 degrees to the wind and will be a close reach. Many dinghy classes have a target length for a race for the first boat. This time might take into consideration the age of competitors, how physically demanding the class is and how physically demanding the conditions are. 100 minutes is often used by Herons in Australia as an informal