The following is an incorrect flowchart proving that point l, lying on line lm which is a perpendicular bisector of segment jk, is equidistant from points j and k:

what is the error in this flowchart?

jl and kl are equal in length, according to the definition of a midpoint.
the arrow between δjnl ≅ δknl and segment jl is congruent to segment kl points in the wrong direction.
segments jl and kl need to be constructed using a straightedge.
point l is equidistant from points j and n, not j and k.