How to Use a Line Level to Calculate Grade, Slope

Don't have a laser level, find grade or slope fast with a string and line level. Learn how to use string a line-level like a pro to see how much rise and run you have on your work area. I'm building a new house and finding elevations with a string level and tape measures and I also go to my desk to show how to find the angle of elevation, what tangent means, and how to use a calculator to find angle and grade as a percent. Find grade with a line level
Good resources: https://www.amazon.com/shop/colfaxmath (paid link)
Mathematics for Carpentry and the Construction Trades, https://amzn.to/3hy0ZUJ