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Just something Dad taught me and I use from time to time on projects, like building decks, laying out walls, or squaring up outside projects. I thought maybe some of you may not have ever heard of it or been exposed to it. The 3-4-5 rule is used to get things laid out square at a 90 degrees.
How it works, is you measure out from the inside or outside corner in one direction and make a mark at 3', then measure out from the same corner the other direction 4'. Now measure from the 3' mark to the 4' mark moving one side in or out until the distance between the marks is 5' exactly, this will be 90 degrees.
You can increase the accuracy for larger projects by multiplying the figures in the rule (i.e. 3-4-5 x 2 = 6-8-10 or 3-4-5 x 3 = 9-12-15). Also it doesn't have to be feet, use inches or centimeters, or even yards if you've got a tape long enough. The math guys call this Pythagoras' theorem.
How it works, is you measure out from the inside or outside corner in one direction and make a mark at 3', then measure out from the same corner the other direction 4'. Now measure from the 3' mark to the 4' mark moving one side in or out until the distance between the marks is 5' exactly, this will be 90 degrees.
You can increase the accuracy for larger projects by multiplying the figures in the rule (i.e. 3-4-5 x 2 = 6-8-10 or 3-4-5 x 3 = 9-12-15). Also it doesn't have to be feet, use inches or centimeters, or even yards if you've got a tape long enough. The math guys call this Pythagoras' theorem.