Triangles (other)
Overview
Important
Beyond the basic types (equilateral, isosceles, scalene), triangles can be classified by their angles (acute, right, obtuse) and by other properties, such as being similar, congruent, or having special points (centroid, incenter, circumcenter, orthocenter).
Important properties
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An acute triangle has all angles less than 90°.
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A right triangle has one angle exactly 90°.
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An obtuse triangle has one angle greater than 90°.
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Triangles can be classified by both sides and angles.
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Special points (centroid, incenter, circumcenter, orthocenter) have unique properties in triangles.