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
Given name Given name A given name (also known as a first name, forename or Christian name) is a part of a person's personal name. It identifies a specific person, and differentiates that person from the other members of a group (typically a family or clan) who have a common surname. The term "given name" refers to the fact that the name usually is bestowed upon a person, normally to a child by his or her parents at or close to the time of birth. A Christian name, a first name which historically was given at baptism, is now also typically given