To draw a straight-line parallel to a given straight-line, through a given point.Let $A$ be the given point, and $BC$ the given straight-line. So it is required to draw a straight-line parallel to the straight-line $BC$, through the point $A$.  <prf>  Thus, the straight-line $EAF$ has been drawn parallel to the given straight-line $BC$, through the  given point $A$.