Hold the angled edgeboard upwards so one end points towards the ground and the other towards the sky. This positioning makes measurement taking significantly easier.
Hold a level at the very end of the edgeboard. Continue adjusting the level until it rests even with the floor. Watch the small air bubble located in the liquid cylinder to level out. The level sits parallel with the ground when the air bubble rests between the two lines marked on the outside of the cylinder. Have a friend or assistant hold the level in place.
Mark off 12 inches on the level using the ruler located on the bottom. Run a tape measure down from the 12-inch mark to the edgeboard. Record the distance.
Place the measurements in the following order: inches in height/inches in distance. For example, suppose the edgeboard has a distance of 9 inches from the 12-inch mark on the level. This means the edgeboard has a pitch of 9/12. This means the edgeboard rises 9 inches for every 12 inches in distance.