Is 78° the exterior of 102° and 43°

If you are referring to angles of a line, 102° and 78° could be angles of a line since a line equals 180°. This would also be the same for an interior triangle angle and it's matching exterior triangle angle. The two angles (102° + 78°) would also equal 180° since they would be supplementary angles.

I would need to see a picture to know what you are referring to with the 45°.

Hope this helps a little at least! :)