- Rectilineal figures are divided into triangles, quadrangles, pentagons, etc. - "Logic, Inductive and Deductive", William Minto.
- Before leaving his rectilineal room, he had dressed himself with his valet Neumann's help with all possible care, as his life in the public eye required. - "Royal Highness", Thomas Mann.
- It is as follows: The straight line drawn at right angles to the diameter of a circle at its extremity will fall outside the circle, and into the space between the straight line and the circumference another straight line cannot be interposed; further, the angle of the semicircle is greater and the remaining angle less than any acute rectilineal angle. - "The Teaching of Geometry", David Eugene Smith.