DIYTried-and-true tip
Check a right angle with the 3-4-5 rule
Check or set out a right angle with the 3-4-5 rule and a folding rule or tape.
- Time
- ⏱ 3 min
- Difficulty
- ◆ easy
What you need
- Folding rule or tape measure
- Pencil
- A corner on the workpiece
How to do it
- From the corner, measure 3 units along one edge and 4 units along the other, and mark both points.
- Measure the diagonal between the two marks; it must be 5 units long.
- If the diagonal matches, the corner is square. If not, adjust it.
Variations
- You can use larger measurements as long as the ratio stays 3 to 4 to 5.
Sources
This is where we found the tip. The badge above shows how well it is backed up.
- heidelberg24.de (opens in a new tab)
Mit dem Zollstock rechten Winkel prüfen – die 3-4-5-Regel hilft“ ; „Die Ziffern stehen dabei für das Längenverhältnis der Seiten eines Dreiecks“ ; „Die Messwerte können natürlich auch variieren – wichtig ist nur das Seitenverhältnis von 3 zu 4 zu 5.
