täisnurk

Täisnurk is an Estonian term that translates to "right angle" in English. It refers to an angle that measures exactly 90 degrees. This specific angle is fundamental in geometry and has numerous applications in various fields. A right angle is formed when two lines or surfaces intersect perpendicularly to each other. Visually, it can be identified by the characteristic square shape of the corner it creates.

In Euclidean geometry, right angles are crucial for defining shapes such as squares, rectangles, and cubes. The Pythagorean theorem, which relates the sides of a right-angled triangle, is a cornerstone of geometry and relies entirely on the presence of a right angle. Many geometric proofs and constructions are based on the properties of right angles.

Beyond pure mathematics, täisnurk plays a significant role in practical applications. In architecture and construction, ensuring that corners are at right angles is essential for structural integrity and aesthetic appeal. Surveying and navigation also heavily utilize the concept of right angles for accurate measurements and positioning. Tools like set squares and carpenter's squares are specifically designed to help create or measure right angles. The concept of a "straight line" is also intrinsically linked to right angles, as a straight line can be thought of as an angle of 180 degrees, and any deviation from perpendicularity is measured in relation to it.