90kraadiseid

90kraadiseid is an Estonian term used in geometry, architecture, and design to describe objects, angles, or layouts that involve ninety-degree measures. The expression derives from the numeral 90 and the adjective kraadine (meaning "degree"), and appears in inflected forms such as 90-kraadine and 90kraadiseid, depending on case and number.

In geometry, 90kraadiseid nurgad are right angles. A rectangle or square has four 90kraadiseid nurgad; a right-angled triangle has one 90kraadine nurg.

In design and drafting, 90kraadiseid layouts imply orthogonal grids where lines meet at right angles, facilitating easy alignment and measurement. The term is primarily used in technical contexts; in everyday Estonian, more common terms are teravnurk (right angle) or 90-kraadine.

Related concepts include teravnurk, orthogonality, and grid systems used in architecture and computer graphics.