**Measurement of Linear Units**

Length answers the question, "How tall, wide, or far is it?"

**History**

The Egyptians have evidence that proves that they may be the earliest civilization that discovered a standard unit for length. The Egyptian

*cubit*was developed about 3000 BC, the unit was based on the length of the arm (from the elbow to the extended finger).

The Greeks used the width of 16 fingers to find one foot. The Romans adopted the foot from the Greeks and divided it into 12 sections which was called

*unicae*, which came to be known as an inch.

The yard was adopted by King Henry I in the 12th century. Many years ago, the US accepted this standard of measurement from London into our customary system.

**Customary Linear Measurements:**

When measuring length in the customary system the common units used are inches, feet, yards, and miles. Units of length measure height, width, length, depth, and distance.

People use "feet" to measure their height. Construction worker and architects use feet to measure walls, floors, and ceilings. It is also used to determine one point to another.

**Facts:**

1. The end of your thumb to your first joint is about 1 inch long.

1. The end of your thumb to your first joint is about 1 inch long.

**2. An egg carton is about a foot long.**

**3. A standard doorway is about a yard in width. A man six-feet tall is 2 yards high.**

**4. Distances between cities are measured in miles.**

**5. From smallest to greatest customary length measurements are compared as:**

**Inches Feet Yards Miles**

**Conversion Chart**

**Customary Measures of Length**

1 foot (ft. or ') =12 inches (in. or ")

1 yard (yd.) = 36 inches (in.)

1 yard (yd.) = 3 feet (ft.)

1 mile (mi.) = 5,280 feet (ft.)

1 mile (mi.) = 1,760 yards (yd.)

When converting any unit of measurements if you want:

- To change to a larger unit,
**divide**. - To change to a smaller unit,
**multiply**

**Metric Linear Measurements:**

In the majority of countries around the world, people use the metric system of measurement.

The metric system is based on 10s. For example, 10 decimeters make a meter (39.37 inches).

Units smaller than a meter have Latin prefixes:

- Deci- means 10; 10 decimeters make a meter.
- Centi- means 100; 100 centimeters make a meter.
- Milli- means 1,000; 1,000 millimeters make a meter.

- Deka- means 10; a dekameter is 10 meters.
- Hecto- means 100; a hectometer is 100 meters.
- Kilo- means 1,000; a kilometer is 1,000 meters.