Q:

# How is a ruler different from a straightedge?

A:

The primary difference between a ruler and straightedge is that a ruler is a measurement device, whereas a straightedge is a tool for drawing or viewing straightness. A ruler is a straightedge with some scale on it so that it can act not only as a straightedge, but also as a device to measure distance. Therefore, a ruler is a straightedge, but a straightedge is not necessarily a ruler.

## Keep Learning

Credit: Daniel Grill N/A Getty Images

A straightedge is a straight instrument used to assist making straight lines for geometric figures. Essentially, this makes it a ruler without the measuring scale. Straightedges are commonly used in automotive and machining industries to determine whether or not machined mating surfaces are flat. Laser line levels can now utilize optics to accurately display a straight line on any surface and determine its straightness. In plane geometry, straightedges are used to draw lines between points, tangents to circles, and any other instance of a straight line. Rulers have multiple designs compared to the straightedge. Some, such as measuring tapes, are straight, L-shaped and retractable. Since the primary function of a ruler, compared to a straightedge, is to measure, some rulers are made curved or flexible so that they can measure the length of things other than straight lines.

Sources:

## Related Questions

• A: The standard unit of measurement for mass is a gram, as designated by the International System of Units (SI). While many industries continue to measure mas... Full Answer >
Filed Under:
• A: Mensuration is a branch of mathematics that deals with the measurement of areas and volumes of various geometrical figures. Figures such as cubes, cuboids,... Full Answer >
Filed Under:
• A: Geometry is the math related to proportions, or size, shape and position, so practical applications of geometry come in measurement and spatial reasoning. ... Full Answer >
Filed Under:
• A: A calibration curve is a mathematical tool used in analytical chemistry that provides a set of reference points that unknown chemical substances can be com... Full Answer >
Filed Under:
PEOPLE SEARCH FOR