þríhyrningum

Þríhyrningum is a term derived from Old Norse and translates to "three corners" or "three angles." It is a geometrical concept referring to a triangle, a fundamental shape in Euclidean geometry. A triangle is a polygon with three edges and three vertices. The sum of the internal angles of any triangle is always 180 degrees.

Triangles can be classified based on their side lengths and angles. By side lengths, they are either equilateral (all sides equal), isosceles (two sides equal), or scalene (no sides equal). By angles, they can be acute (all angles less than 90 degrees), right (one angle exactly 90 degrees), or obtuse (one angle greater than 90 degrees).

The study of triangles is called trigonometry, which explores the relationships between the sides and angles of triangles and is crucial in fields like astronomy, engineering, and physics. The concept of þríhyrningum, or triangles, has been recognized and utilized since ancient times, forming a foundational element of geometry and mathematics. Its simplicity and versatility make it a pervasive shape in both natural and man-made structures.