Definition:Angle/Rectilineal
< Definition:Angle(Redirected from Definition:Rectilineal Angle)
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Definition
In the words of Euclid:
- And when the lines containing the angle are straight, the angle is called rectilineal.
(The Elements: Book $\text{I}$: Definition $9$)
Thus the distinction is made between straight-line angles and curved-line angles.
Most of the time the fact that angles are rectilineal is taken for granted.
Also known as
The term is also seen as rectilinear.