# Cut straight line with knife tool

Im trying to create a face in order to extrude upwards to create a wall for my church building. In order to do that I figured I make a cut with the knife tool like so:

Ideally that line would be straight and I know that I can press A to have some angle. However since the object is not aligned it gives me angles that arent useful:

Is there a way to manipulate the angle so that it gives me a straight line? If not, is there another way to reach my desired goal?

If you select any piece of geometry and then press Shift+<Numpad Direction Number e.g. 1, 3, 7> it will align the camera to that geometries normal.
So if you select the edge you want, then press Shift+Numpad7 to align to the top view of that edge, you can then use the knife tool and press A to constrain your cut to a 45 degree increment.