Measuring Existing Wall Angles

[lgswe]

I've been in house construction for over 30 yrs. What I found works best is to have a few straight edges of different lengths. Take the two longest ones you can use and put them in the corner with each one running along the two walls out of the corner. Then measure the distance between the outside ends of the two straight edges and calculate. This way you'll have the known length of all three sides of your triangle. The longer your straight edges the more accurate your angle will be.