Science, Maths & Technology
Geometry
...open as wide as possible. [Obtuse angle] Figure ang3 Half turn (Straight angle) This corresponds to a straight line; it is exactly 180°. The pages of an open book that is lying flat approximately describe a half turn. [Half turn (Straight angle)] Reflex angle Any angle that is between a half turn and a complete turn; that is, between 180° and 360°. When a box is opened...