Grade 10 → Mensuration ↓
Conversion of Units
Conversion of units is an essential skill in mathematics, not only for solving problems in everyday life but also in various fields including science, engineering, and commerce. Units are used to measure quantities and when we talk about conversion of units, we are referring to the practice of converting one measurement unit into another.
It is important to understand units and be able to convert them because different systems of measurement are used in the world. The most common systems include the metric system and the imperial system.
Metric system
The metric system, which originated from France, is the most widely used measurement system. It is based on the number 10, which makes it convenient as it aligns well with the decimal number system.
The basic units in the metric system are meters for length, grams for mass, and liters for volume. From these base units, you can get larger or smaller units by adding prefixes:
- milli- : 1/1000 or 0.001
- centi- : 1/100 or 0.01
- deci- : 1/10 or 0.1
- deca- : 10
- hecto- : 100
- kilo- : 1000
For example:
- 1 meter = 1000 millimeters
- 1 gram = 1000 milligrams
- 1 litre = 1000 millilitres
Imperial system
The imperial system, often used in the United States, primarily consists of measurements such as inches, feet, yards, and miles for length; ounces and pounds for weight; and pints, quarts, and gallons for volume.
For example:
- 1 foot = 12 inches
- 1 yard = 3 feet
- 1 mile = 5280 feet
Why convert units?
Conversion is required when measurements are given in different units. For example, if you have a length measurement in meters and you need it in centimeters, a conversion is needed. Similarly, it may be necessary to convert liters to milliliters or grams to kilograms depending on the need or context of the problem being solved.
Basic conversion formulas
Below are some formulas for converting between common units:
Length conversion
Metric system:
1 kilometer = 1000 meters
1 meter = 100 centimeters
1 centimeter = 10 millimeters
Imperial system:
1 mile = 1760 yards
1 yard = 3 feet
1 foot = 12 inches
Mass conversions
Metric system:
1 kilogram = 1000 grams
1 gram = 1000 milligrams
Imperial system:
1 pound = 16 ounces
Conversion example
Example 1: Length conversion
Convert 5 kilometers to meters:
Since 1 kilometer is equal to 1000 meters, you multiply:
5 km = 5 × 1000 = 5000 meters
Example 2: Volume conversion
Convert 3 liters to milliliters:
1 liter is 1000 millilitres, so:
3 liters = 3 × 1000 = 3000 milliliters
Example 3: Mass conversion
Convert 2500 grams to kilograms:
Since 1 kilogram is 1000 grams, you would divide it like this:
2500 g = 2500 / 1000 = 2.5 kilograms
Converting between metric and imperial
Sometimes you may need to convert between the metric and imperial systems. Here are some approximate conversions:
1 inch = 2.54 centimeters
1 foot = 30.48 centimeters
1 yard = 0.9144 meters
1 mile = 1.60934 kilometers
1 pound = 0.453592 kilograms
1 ounce = 28.3495 grams
Example 4: Imperial to metric conversion
Convert 10 miles to kilometers:
1 mile is approximately 1.60934 kilometers, so:
10 miles = 10 × 1.60934 = 16.0934 kilometers
Example 5: Metric to imperial conversion
Convert 50 kilograms to pounds:
1 kilogram is approximately 2.20462 pounds, so:
50 kg = 50 × 2.20462 = 110.231 pounds
Conclusion
Knowledge of unit conversions is vital for accurate interpretation and communication of measurements. Whether in academia, professional life, or everyday activities, these conversions allow for consistency and universality in measurements.
Practicing these conversions helps hone the skill of easily converting measurements from one system to another, ensuring accuracy and fluency when working with different units of measurement.