Ruler
Encyclopedia : R : RU : RUL : Ruler
- This article is about the drawing and measuring instrument. Ruler can also refer to a statesman in charge or ceremonial head of state of a country or minor politically significant principality; for this meaning see Monarch or Lists of incumbents.
A ruler or rule is an instrument used in geometry, technical drawing and engineering/building to measure distances and/or to rule straight lines. Strictly speaking, the ruler is the instrument used to rule lines and the calibrated instrument used for determining measurement is called a measure. However, common usage is that a ruler is calibrated so that it can measure.
Several different designs of flexible instruments are used to determine length, such as the carpenter's rule, the ribbon-like tape measure used by tailors, and the retractable rule used especially in the construction trades and by home handyman, also known as a tape measure. As can be seen by the photos on this page, a 2 metre carpenter's rule can be folded down to a length of only 20 centimetres to easily fit in a pocket, and the 5 metre long tape easily retracts to fit within a small-sized housing.
Practical rulers have distance markings along their edges. How these distance markings are applied and calibrated should be described here, including a history of old methods.
- The ruler (calibrated, though numbers are not shown) appears as a charge in heraldry, notably in the arms of Odouze.
Geometric constructions
- ''Main article: Compass and straightedge
See also
- Architect's scale
- Engineer's scale
- Golomb ruler
- Perfect ruler
- Rulering (punishment)
- Slide rule
- Tape measure
Sources and external link
- [Printable rulers] in PDF format
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