Interpret Pitch Measurement

What happens here

Once the horizontal arm of the framing square is perfectly level, observe the vertical arm. Read the numerical measurement on the vertical arm where it intersects with the underside of the roof decking or the top edge of the eave (depending on how the square is held). This number represents the 'rise' in inches for every 12 inches of 'run'. In the video, the reading is '4', indicating a 4/12 roof pitch.

Goal: Determine the roof pitch