+A **triangle** is a [polygon](/wiki/polygon) with three straight sides and three [vertices](/wiki/vertex). It is a fundamental [shape](/wiki/shape) in [geometry](/wiki/geometry), its internal angles always summing to 180 degrees.
+## See also
+- [Angle](/wiki/angle)
+- [Trigonometry](/wiki/trigonometry)
+- [Area](/wiki/area)
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