Given two unequal straight lines, to cut off from the greater a straight line equal to the less. • Start with the line segments AB and C, with AB greater than C. • Let line AD be created from point A, equal to line C (see Proposition 2). • Create the circle DEF around point A with a radius of AD. • Place point E on the intersection of the circle DEF and the line AB. The line AE has been created on line AB equal to line C.