I'm learning to use Blender and still getting to grips with the basics. I've tried searching for an answer to this, but can't find one. Maybe I'm just not using the correct terms etc in my search.
I'm trying to extrude the 4 selected faces (see pic below) outwards diagonally between the X and Y axis by 0.8 units while keeping it's position on the Z axis at 0.
I've tried using a top down view (Num Pad 7) which seems to keep the Z axis at 0, but then I can't use the keyboard to enter 0.8 because as soon as I do it applies it to the X axis and extrudes in the wrong direction (I haven't locked or selected an axis). I've also tried changing the transformation orientation from Global to local/normal, etc.
I also thought of extruding the faces directly on one axis and then rotating the entire object, but thought this may not be easy to do with more complex models in future. When I did this however I encountered another problem. The extruded edges don't continue in the same direction as the originals. If you look at the picture below, what I mean is I want the left and right edges of the extruded section to be where I've drawn the red lines (I.e. keeping the triangular shape)
Hope all this makes sense.