Special right triangle : , which follows immediately from the Pythagorean theorem. Of all right triangles, the 45°–45°–90° degree triangle has the smallest ratio of the hypotenuse to the sum of the legs, namely . Of all right triangles, the 45°–45°–90° degree triangle has the greatest ratio of the altitude from the hypotenuse to the sum of the legs, namely . Triangles with these angles are the only possible right triangles that are also isosceles triangles in Euclidean geometry. However, in spherical geometry and hyperbolic geometry, there are infinitely many different shapes of right isosceles triangles. This is a triangle whose three angles
Jack (given name) Jack (given name) Jack is a male given name. In recent decades, Jack has become one of the most common names for boys in many English-speaking countries. While Jack is now a proper name in its own right, in English; it was traditionally used as a diminutive form of John. It can also be used as a diminutive for: Jacob, Jason, Jonathan, Johann, Johannes, Joachim and sometimes for James, from its French form Jacques. It is also used as a female given name (often a shortened version of Jacqueline or Jackie) and as a surname to a lesser extent. The