Kulmakulmat

Kulmakulmat are the measures of angles formed by two intersecting lines or segments that share a common endpoint. In Finnish geometry, they describe the corner-like openings found in polygons and other shapes, and they are a fundamental way to describe orientation and shape. Kulmakulmia are measured in degrees or radians, and they quantify how open or closed a corner is. The notation for an angle at a vertex B formed by points A–B–C is written as ∠ABC, and its size is the measure m∠ABC.

In a polygon with n sides, the sum of its interior kulmakulmat is (n−2)×180 degrees. Exterior kulmakulmat, defined as the angle outside the polygon when a side is extended, typically sum to 360 degrees for a simple polygon when considering one exterior angle at each vertex. In right triangles, the kulmakulma at the right angle is 90 degrees, while the other two angles are complementary, summing to 90 degrees.

These angles are central in many fields, including architecture, computer graphics, surveying, and navigation, where angular measurements relate to the layout, orientation, and rendering of objects. In trigonometry, the ratios of side lengths in relation to kulmakulmat are described by sine, cosine, and tangent functions. The term kulmakulmat is part of standard Finnish mathematical vocabulary and appears in school textbooks and academic writing when discussing corner angles and angular relationships.