How to extend planes and find intersection point

I’m new to blender. I want to restore sharp edge and create vertex that is geometrically intersection of selected triangles. Is there fast way to do this?
selected triangles are orange

>Solution :

This isn’t very easy to do without changing the volume of the mesh, but here’s the best method I’ve found:

1. Select the whole mesh (Or just the bevelled faces you want to sharpen):

2. Select the "Shrink/fatten" tool from the toolbar:

3. Shrink the faces, until the vertices at the corners are overlapping.
   IMPORTANT: if you want to preserve the volume of the object, make sure to make a note of the exact value that you shrank the mesh by (visible in the bottom left of the screen):

4. Press the M key and select Merge by distance (or go to Mesh > Merge > By distance), and increase the Merge distance parameter until all of the vertices double vertices have been merged:

5. Finally, use the shrink/fatten tool again to resize the mesh to its original volume. (If you want to be exact, use the negative version of the amount you shrunk it by to begin with):

Bonus tip, if you want to get rid of the annoying triangles on the faces, you can use the Tris to quads operator to remove them.