UNITS OF LENGTH

• History
• Units of Length
  • Reading a Ruler
• Conversion Chart
• Drill and Practice

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

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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.

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Units of Length

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.

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

An egg carton is about a foot long.

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

Distances between cities are measured in miles.

From smallest to greatest length measurements are compared as:

Inches

Feet

Yards

Miles

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Reading a Ruler

When reading a ruler, you want to find out how far the item is from zero. When reading a ruler, you must locate the zero marking, this may vary depending on the ruler. On some rulers, the zeros start at the end, but on others it starts about 1/4 of an inch from the end. If you do not check your ruler beforehand you will not be getting an accurate measurement.

Point A is 1 1/4 inches or 1 1/4 inches away from zero.

Point B is 3 3/4 inches or 3 3/4 inches away from zero.

Point C is 4 1/8 inches or 4 1/8 inches away from zero.

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Conversion Chart

When converting any unit of measurements if you want:

• To change to a larger unit, divide.
• To change to a smaller unit, multiply.

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Click on the pencil of the measurement which accurately answers the amount of length each item would be.

1. The length of a river

	25 inches
	25 miles

2. The size of the length of a photo

	7 inches
	7 feet

3. The thickness of a phonebook

	4 feet
	4 inches

4. The height of a child's bicycle

	20 feet
	20 inches

5. The depth of water in a bathtub

	8 inches
	8 feet

Answer the next questions on a sheet of paper and turn them in when you have completed them.

Write the equivalents.

6) 6 inches = ______foot

7) 10 feet = _____yards_____feet

8) 30 feet = ________inches

9) 7,258 feet = _____ miles _____yards _____feet

10) 5,789 yards = _______miles______yards

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