Hatch mark
From Wikipedia, the free encyclopedia
For other uses of "Hash mark", see Hash.
Hatch marks (also called hash marks or tick marks) are a form of mathematical notation. They are used in three ways as:
- Unit and value marks — as on a ruler or number line
- Congruence notation in geometry — as on a geometric figure
- Graphed points — as on a graph
Hatch marks are frequently used as an abbreviation of some common units of measurement. In regard to distance, a single hatch mark indicates feet, and two hatch marks indicate inches. In regard to time, a single hatch mark indicates minutes, and two hatch marks indicate seconds.
In geometry and trigonometry, such marks are used following an elevated circle to indicate degrees, minutes, and seconds — ( ° ) ( ′ ) ( ″ ).
Hatch marks can probably be traced to hatching in art works, where the pattern of the hatch marks represents a unique tone or hue. Different patterns indicate different tones.