Segment trisection without compass I'm trying to figure out how to trisect a segment using only pen and ruler.
There is a parallel line provided.
No measurement is allowed.

lets mark ends of the segment as A and B.


*

*mark points C and D on the parallel line.

*draw lines BD and AC, mark the cross point as E

*draw lines BC and AD, mark the cross point as F

*draw line EF, mark its cross point with line CD as G

*draw line BG, mark its cross point with line AD as H


The line EH cuts segment AB in 2:1 ratio.
