Consider the following construction.
Given a line segment AB. Construct a perpendicular segment BD such that 2BD = AB. Draw AD. Mark point E on AD such that DE = DB. Mark point F on AB such that AE = AF
Given a line segment AB.
Construct a perpendicular segment BD such that 2BD = AB.
Draw AD.
Mark point E on AD such that DE = DB.
Mark point F on AB such that AE = AF