Ruler

Ruler

A ruler or measuring stick is a tool used in geometry, technical drawing, printing as well as engineering and building to measure distances or to draw straight lines.

History

The use of the ruler dates back to ancient times. The oldest preserved measuring rod is a copper-alloy bar that dates from c. 2650 BC and was found by the German Assyriologist Eckhard Unger while excavating at Nippur. Rulers made of ivory were in use by the Indus Valley Civilization period prior to 1500 BC.

Types of Rulers

There are several types of rulers, including the yardstick, the straightedge or line gauge, and the tailor's ruler.

Yardstick

A yardstick is a straightedge used to physically measure lengths of up to a yard (3 feet or 0.9144 meters).

Straightedge or Line Gauge

A straightedge or line gauge is a tool used in the printing industry. It is a ruler that is used to cut paper in a straight line.

Tailor's Ruler

A tailor's ruler or French curve is a ruler that has a shape that is useful for drawing curves. It is used in tailoring and dressmaking.

Units of Measurement

Rulers have measurements in imperial units, metric, or both. In the United States, rulers usually have both measurements to accommodate for both systems.

Use in Mathematics

In mathematics, a ruler without any marks on it (a straightedge) can be used with a compass to find the midpoint of a line segment, to draw a line through a given point parallel to a given line, or to inscribe a regular polygon in a given circle or circumscribe a regular polygon about a given circle.

See Also

• Tape measure
• Calipers
• Slide rule
• Ruler function

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