Euclid's Postulates and Common Notions

Postulate 1

to draw a straight line from any point to any point

Postulate 2

to produce a finite straight line continuously in a straight line

Postulate 3

to describe a circle with any center and distance

Postulate 4

that all right angles are equal to one another

Postulate 5

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 indefinitley, meet on that side on which are the angles less than the two right angles

CN 1

things that are equal to the same thing are also equal to each other

CN 2

if equals be added to equals, the wholes are equal

CN 3

if equals be subtracted from equals, the remainders are equal

CN 4

things which coincide with one another are equal to one another

CN 5

the whole is greater than the part