# Construction by compass and straightedge.

l,m,n are three concurrent line concurrent at point A. Given a point B on line l. Is it possible to construct point C on line n such that line m is a median of triangle ABC

• This sounds to me like something that would demand a marked straightedge. But I'm not certain. – Arthur Mar 25 '14 at 12:58

Yes, for sure. Take a point $P$ on $n$: the midpoint of $BP$ is on a line parallel to $n$ through the midpoint of $AB$, so you can find the midpoint of $BC$ by intersecting $m$ with the parallel to $n$ through the midpoint of $AB$.