Testing a square corner
A carrom board has a damaged corner. Is the corner still square?
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The rule
Two lines that meet at a square corner are perpendicular. The turn between them is 90°, ninety degrees. Each line is called an arm of the corner.
Mark 30 mm out on each arm. The mm means millimetres. Measure the gap between the two marks. A square corner gives 42 mm.
Step 1 of 3
- A corner has two arms.
- Mark the same distance out on each arm.
- Measure the gap between the two marks.
A square corner leaves a 42 mm gap for 30 mm marks. Make the corner wider and the gap grows. Make it narrower and the gap shrinks.
Example
Marks 30 mm out. A square corner would give 42 mm. The gap reads 46 mm.
46 is more than 42. So the corner is wider than square.