täisnurkse

"Täisnurkse" is an Estonian adjective meaning "right-angled" or "rectangular". It is derived from the noun "täisnurk", which translates to "right angle". This term is primarily used in geometry to describe shapes that possess at least one, and in the case of a rectangle, four, right angles.

A täisnurkne kolmnurk, or right-angled triangle, is a triangle in which one of the interior angles measures exactly 90 degrees. The sides adjacent to the right angle are called legs, and the side opposite the right angle is called the hypotenuse. The Pythagorean theorem, which states that the square of the hypotenuse is equal to the sum of the squares of the other two sides, is a fundamental property of täisnurksed kolmnurgad.

A täisnurkne nelinurk, or rectangle, is a quadrilateral with four right angles. Opposite sides of a rectangle are equal in length and parallel. Its area is calculated by multiplying its length and width. The term can also be used more broadly to describe any object or structure that has a rectangular form or is oriented at a right angle to something else, such as a täisnurkne raam (rectangular frame).