The English System of Measurement
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The English system of measurement grew out of the creative way that people measured for themselves.  Familiar objects and parts of the body were used as measuring devices.  For example, people measured shorter distances on the ground with their feet.

 They measured longer distances by their paces (a "mile" was a thousand paces).  They measured capacities with common household items such as cups, pails, and baskets.  The word gallon comes from an old name for a pail.  

Unfortunately, these creative measuring devices allowed for different measurements to be obtained when different people measured the same items.  Eventually, a standard was set so that all measurements represented the same amount for everyone.



12 inches (in) = 1 foot (ft)
3 feet  = 1 yard (yd)
 5280 feet = 1 mile (mi)



3 teaspoons (tsp) = 1 tablespoon (tbsp)
 16 tbsp = 1 cup (c)
8 ounces (oz) = 1 c
2 c = 1 pint (pt)
2 pt = 1 quart (qt)
4 qt = 1 gallon (gal)


16 ounces (oz) = 1 pound (lb)
2000 lb = 1 ton




Sometimes you need to convert from one unit of measure to another similar unit.  How many inches are in 3 feet?  How many ounces in 5 pounds?


Proportions will help you make conversions when working with measurements.

Create a unit conversion ratio, which is always equal to 1:





Example 1:  How many yards are in 15 feet?

There are 3 feet in one yard, so the conversion ratio is 1 yd / 3 ft:

Solving algebraically gives an answer of 5 yards.




Example 2:  How many cups in one gallon?

There is no direct connection from cups to gallons.  There are, however, 4 cups in one quart and 4 quarts in one gallon.  So the conversion ratio could be:

Solving algebraically gives an answer of 16 cups.