quotation from the apex

[deep70]

Hello everyone,
simple question I imagine for most of you..
I have to quote correctly from the apex or angle crossing given by a sheet with a bend of 45°.
place a couple of image where I put the odd in incorrect position in the first to better make the concept, while for the second I extended the edges through sketch.
thanks to all in advance for the answers given.

 

[volaff]

click on the first line, then holding ctrl click the second line and then with the mouse on the point icon.
should put a point (virtual shape) to the intersection of the two lines so that you can quote.