Equilateral polygon with 60° internal angles. An equilateral quadrilateral is called a rhombus, an isotoxal polygon described by an angle α. It includes the square as a special case. A convex equilateral pentagon can be described by two angles α and β, which together determine the other angles. Concave equilateral pentagons exist, as do concave equilateral polygons with any larger number of sides. An equilateral polygon which is cyclic (its vertices are on a circle) is a regular polygon (a polygon that is both equilateral and equiangular). A tangential polygon (one that has an incircle tangent to all its sides) is equilateral
Golden Triangle (Rocky Mountains) Golden Triangle (Rocky Mountains) The Golden Triangle is an informal designation for a region renowned as one of the premier fly fishing locations in the United States. The region is named for its approximate boundaries that form an equilateral triangle having an apex at Glacier National Park and encompassing Yellowstone National Park and the eastern portion of Idaho. Superior fly fishing also exists in the surrounding areas of the Rocky Mountains in Idaho and western Montana. Because of a large number of major rivers such as the Yellowstone, Madison, Gallatin, and the Blackfoot, many hundreds of fast, clear-running streams and