Perpendikulaarsest

Perpendikulaarsest is an Estonian word that translates to "perpendicular" in English. It describes the geometric relationship between two lines or planes that intersect at a right angle, meaning they form a 90-degree angle. In Euclidean geometry, perpendicularity is a fundamental concept used in various theorems and constructions. For example, the altitude of a triangle is a line segment from a vertex perpendicular to the opposite side.

The concept of perpendicularity is crucial in coordinate geometry. Two lines with slopes m1 and m2 are perpendicular if their product is -1, i.e., m1 * m2 = -1 (provided neither line is vertical or horizontal). Vertical lines are perpendicular to horizontal lines. This property is widely applied in analytical geometry to solve problems involving distances, equations of lines, and properties of geometric figures.

In three-dimensional space, two lines are perpendicular if the angle between their direction vectors is 90 degrees. Similarly, two planes are perpendicular if the angle between their normal vectors is 90 degrees. This concept extends to vectors, where the dot product of two perpendicular vectors is zero. The term "perpendikulaarsest" thus encapsulates this precise geometric condition of meeting at a right angle, a concept universally understood in mathematics and its applications.