exterior angle

noun

, Geometry.

1. an angle formed outside parallel lines by a third line that intersects them.
2. an angle formed outside a polygon by one side and an extension of an adjacent side; the supplement of an interior angle of the polygon.

exterior angle

noun

1. an angle of a polygon contained between one side extended and the adjacent side
2. any of the four angles made by a transversal that are outside the region between the two intersected lines

exterior angle

/ ĭk-stîr′ē-ər /

1. The angle formed between a side of a polygon and an extended adjacent side.
2. Compare interior angle

Word History and Origins

Origin of exterior angle¹

First recorded in 1885–90

Example Sentences

It is in the form of a square, built round an inner courtyard, and has an immense bastion at each exterior angle.

From Project Gutenberg

If one side of a triangle be produced, the exterior angle shall be greater than either of the interior opposite angles.

From Project Gutenberg

The sharp edge formed by two surfaces meeting at an exterior angle.

From Project Gutenberg

Posterior wings white, with a sooty spot on each near the external edge, and a very faint small mark near the exterior angle.

From Project Gutenberg

The proposition relating to the exterior angle was recognized by Pappus of Alexandria.

From Project Gutenberg