If you intersect 3 lines, you will obtain a (or some) dot(s). If you want to do this, you can use "intersect" tool for 2 of your 3 lines (the result is "curve1"), then use your third line and extrude it as a surface (it has to intersect "curve1"). You can now create a point (or some points, depending on your lines shapes) that will be on curve1 and on the extruded surface.
