Let the following be postulated:
To draw a straight line from any point to any point.
To produce a finite straight line continuously in a
To describe a circle with any centre and distance.
That all right angles are equal to one another.
That, if a straight line falling on two straight lines
make the interior angles on the same side less than
two right angles, the two straight lines, if produced
indefinitely, meet on that side on which are the angles
less than two right angles.