Question

the measures of an exterior angle and the adjacent interior angle add p to 360 because they form a linear plane?

Answer 1

Sadly, I can't see the picture you're looking at as you make that statement.
But I'm pretty sure that when you combine an exterior angle with the interior
angle adjacent to it, you'll wind up with 180°, because they form a linear line.
There actually isn't any such thing as a linear plane.