Cannot erase lines in a sketch

[KarolR]

I made a projection of a 2D sketch on a conical surface but it projected on both sides. i want to erase the lines that are on one side, but although i select the lines and press delete-nothing happens.

I also tried window selecting and pressing delete-the same.

Part3.ipt

[JD Mather]

Your sketch is not constrained not symmetrical.

on the 3D sketch simply change to construction linetype rather than trying to delete.

[JD Mather]

What are you going to do with the 3D sketch?

Split Face might be a better option.

But first you should clean up the 2D sketch.

[KarolR]

I didn't see correctly the sketch because it is inside the solid and i didn't know how to make the solid transparent. i right clicked on the solid but didn't find the visibility option

[JD Mather]

F7 while in sketch or set Visual Style to wireframe.

You should be able to create a sketch like that and have Inventor automatically apply tangent constraints.

Click and drag arc of of lines while still in line command.

[KarolR]

the button to convert a line to construction doesn't exist in 3D sketch, or i cannot find it in version 2009.

And i cannot delete projected lines in 3D sketch, maybe because there is a connection to the original geometry?

Part3.ipt