Lähikulmaukset

Lähikulmaukset, often translated as "adjacent angles" or "neighboring angles," are a pair of angles that share a common vertex and a common side, but do not overlap. This means that the rays forming the angles are distinct, except for the shared ray. In essence, adjacent angles lie next to each other.

A key property of adjacent angles is that when they form a straight line, they are called a linear pair. The sum of the measures of angles in a linear pair is always 180 degrees. This is because a straight line represents an angle of 180 degrees, and the two adjacent angles together comprise this entire angle.

Adjacent angles are a fundamental concept in geometry and are used in various proofs and calculations. For instance, understanding adjacent angles is crucial when dealing with parallel lines intersected by a transversal, where specific relationships between angles, such as supplementary angles, are established. The concept also applies in polygons, where angles along the same side can be considered adjacent. When two lines intersect, four angles are formed, and these can be grouped into two pairs of adjacent angles, each pair summing to 180 degrees, and two pairs of vertical angles, which are opposite to each other and equal in measure.