I need to build an arbor between my garage and my house and I need to know how to line up the beams so they are perpendicular to both buildings. They are 15' apart and they are parallel with each other, but one is set back from the other, so I can't just measure from the end. All I am coming up with is the 3-4-5 rule, but I doubt I will be accurate enough with that. Any ideas?
Thanks, Steve
P.S. I hope this is the right forum for this question.