TOOLS / LAYOUT

Right-triangle and 3-4-5 layout calculator

Solve a right triangle from two legs, a leg and the hypotenuse, or a leg and an angle — for squaring foundations, frames and machine bases.

Triangle result5.00 hypotenuse

Legs 3.00 and 4.00 · angles 36.87° and 53.13° (plus 90°) · 3-4-5 check: multiples of 3, 4, 5 give a square corner

Layout aid for squaring foundations, frames and machine bases. Verify with a tape on both diagonals before fixing — a single triangle does not prove a full rectangle square.

Formula

Pythagoras: hypotenuse² = leg A² + leg B². Angles from sine, cosine and tangent; the two acute angles sum to 90°.

Standard / source

Plane trigonometry — the 3-4-5 triangle is the classic field square check: any multiple of 3, 4 and 5 gives a right angle.

Worked example

Legs 3 and 4: hypotenuse = √(3² + 4²) = 5. Angles = atan(3/4) ≈ 36.87° and atan(4/3) ≈ 53.13°.

Safety note

Layout aid only. Verify with a tape on both diagonals before fixing — a single triangle does not prove a full rectangle square.