An example of modern architecture, designed with many right angles.

In geometry and trigonometry, a right angle is an angle of 90 degrees, corresponding to a quarter turn (that is, a quarter of a full circle). Geometry ( Greek γεωμετρία; geo = earth metria = measure is a part of Mathematics concerned with questions of size shape and relative position Circle-trig6svg|300px|thumb|right|All of the Trigonometric functions of an angle θ can be constructed geometrically in terms of a unit circle centered at O. This article describes the unit of angle For other meanings see Degree. It can be defined as the angle such that twice that angle amounts to a half turn, or 180° ^[1]. In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called

Lines that are at a right angle to each other are perpendicular, an important geometrical property. In Geometry, two lines or planes (or a line and a plane are considered perpendicular (or orthogonal) to each other if they form congruent The presence of a right angle in a triangle is the defining factor for right triangles. A triangle is one of the basic Shapes of Geometry: a Polygon with three corners or vertices and three sides or edges which are Line Two types of special right triangles appear commonly in geometry the "angle based" and the "side based" (or Pythagorean Triangles The former are characterised

A right angle may be expressed in different units:

• 90°
• ^π/₂ radians
• 100 grad (also called grade, gradian, or gon)
• 8 points (of a 32-point compass rose)
• 6 hours (astronomical hour angle)
• ∞% grade on the tangent scale
• 100% grade on the sine scale. The radian is a unit of plane Angle, equal to 180/ π degrees, or about 57 The grad is a unit of plane Angle, equivalent to of a full Circle, dividing a Right angle in 100 For Compass Airlines an Airline in the US using the Callsign "Compass Rose" See Compass Airlines A compass rose is a figure displaying the orientation In Astronomy, the hour angle is one of the coordinates used in the Equatorial coordinate system for describing the position of a point on the Celestial sphere The grade (or gradient or pitch or slope) of any physical feature such as a Hill, Stream, Roof, railroad, or

The term is a calque of Latin angulus rectus; here rectus means "upright", referring to the vertical perpendicular to a horizontal base line. In Linguistics, a calque (kælk or loan translation is a Word or Phrase borrowed from another Language by Literal, word-for-word Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome.

See also

• Angle: Types of angles
• Orthogonality
• Perpendicular
• Cartesian coordinate system
• Rectangle

References

1. ^ Lindahl, G. In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called In Mathematics, two Vectors are orthogonal if they are Perpendicular, i In Geometry, two lines or planes (or a line and a plane are considered perpendicular (or orthogonal) to each other if they form congruent In Mathematics, the Cartesian coordinate system (also called rectangular coordinate system) is used to determine each point uniquely in a plane In Geometry, a rectangle is defined as a Quadrilateral where all four of its angles are Right angles A rectangle with vertices ABCD would be denoted as (1987). Euklides Geometri. Stockholm, Natur och kultur: ISBN 91-27-72185-X