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Standard Units

You are probably familiar with a lot of these measurements. Length is about a distance. These distances answer questions with "how far?", "how long?", and "how high?".

1 foot = 12 inches (inches are usually divided into sixteenths on a ruler)
1 yard = 3 feet = 36 inches
1 mile = 1,760 yards = 5,280 feet = 63,360 inches

Metric Units

The basis of length units for the metric system is the meter. A meter is about the same length of one yard. You already read that the metric system is based on units of ten so here's a starter list, but they go on forever.

1 centimeter = 10 millimeters
1 meter = 100 centimeters = 1,000 millimeters
1 kilometer = 1,000 meters = 100,000 centimeters = 100,000,000 millimeters = 1*10⁸ millimeters

Conversion

You're going to have to go back and forth with units. Converting inches in to centimeters and feet into meters is a regular thing in math and science classes. Here are a few conversions. Technically you only need one conversion, but sometimes it's easier to use one closer to the values you want.

1 inch = 2.54 centimeters = 25.4 millimeters
1 foot = 30.48 centimeters
1 yard = 0.91 meters
1 mile = 1.6 kilometers

1 millimeter = 0.04 inches
1 centimeter = .39 inches = 0.0325 feet
1 meter = 3.28 feet
1 kilometer = 0.62 miles

Example

So if I'm going to run a 5K race over the weekend, how many miles will I run?
5 kilometers = 5 * 0.62 miles = 3.1 miles

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