Simple Solutions

How to Find Square Layout Lines

By: Joe Truini

If laying out square lines is part of your next home improvement project, here’s a great way to do it using the Pythagorean theorem (A² + B² = C²) to form a right angle triangle with 3′ and 4′ sides and a diagonal of 5′:

  1. Establish a 4′ line parallel to a wall.
  2. Measure out 3′ from one end of the 4′ line roughly perpendicular to it.
  3. Hold a tape measure on the other end of the 4′ line.
  4. Measure 5′ so it forms a triangle with the end of the 3′ line.
  5. Adjust the angle of the 3′ line until the tape measure aligns with it.


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2 Comments on “How to Find Square Layout Lines”

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  • Official Comment:

    Lindsay Hughes Says:
    June 15th, 2016 at 10:39 am

    Jonas, 5 is correct. Take the square root of 25 to find the hypotenuse.


  • jonas Says:
    June 14th, 2016 at 9:26 am

    I know this must be an oversight, but the theory is (axa)+(bxb) = (cxc)
    (can’t squared easily on keyboard)
    so 3×3+4×4=5×5
    not 3+4=5
    so 9+16=25

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How to Find Square Layout Lines