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Introduction to Units
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As we begin the lesson on Perimeter, Area, and Volume, we begin to have a need for units. Units tell us what the number means. The following video will explain many different types of units which you will use throughout your life.

Introduction to Units

Units are the words we use to describe what numbers represent. Just a few examples of units include things like inches, centimeters, pounds, kilograms, degrees, feet, seconds, hours, etc. There are hundreds of types of units in this world.

### Real World Application

What is a unit you use frequently in your life? You might use it in your work, home, cooking, or measuring. Anything you measure requires a unit.

### Practice Problems

1. Which of the following units are used to measure temperature? (
Solution
Solution:
b.
)
a. Ounces (oz)
b. Degrees Celsius (°C)
c. Kilograms (kg)
d. Inches (in)
2. Which of the following units are used to measure length? (
Solution
Solution: a.
Details:
The Unit to measure Length is Meters (m).

Length is measured with a ruler or tape measure or something else that measures distance. Examples of common units that measure length are millimeters, centimeters, meters, kilometers, inches, feet, yards, miles, etc.

In the past, it was common for different cultures to use different units to measure length. For example, in Algeria, they used to measure length using a termin and a pic while in ancient China they used to use the Shang and Zhou.

In this question, the only unit to measure length is the meter. Pounds measure weight, liters measure volume, and Fahrenheit measures temperature, so these can not be used to measure length.
)
a. Meters (m)
b. Pounds (lbs)
c. Liters (L)
d. Degrees Fahrenheit (°F)
3. Which of the following units are used to measure area? (
Solution
Solution: c.
Details:
Area is the measurement of a surface. It is the measurement of a flat piece of space. Area is like the size of a piece of land or the amount of floor space that could be covered by a rug.

It takes two directions of length to measure area: length and width, or width and height, or some other appropriate combination. When these two lengths are multiplied together the units become squared or raised to the 2nd power.

Thus the units for area usually have an exponent of 2. However, this is not always the case. There are some units for area that specifically refer to area and thus don’t need the exponent.

Examples of this are the acre and hectare. In this question, the exponent 2 on $${\text{ft}}^2$$ gives away that it is a measurement of area. A liter is a measurement of volume, Celsius is a measurement of temperature, and miles measure length.
)
a. Liter (L)
b. Degrees Celsius (°C)
c. Square feet ($${\text{ft}}^2$$)
d. Miles (mi)
4. Which of the following units are used to measure area? (
Solution
Solution:
c.
)
a. Quart (qt)
b. Degrees Celsius (°C)
c. Square centimeters ($${\text{cm}}^2$$)
d. Miles (mi)
5. Which of the following units are used to measure time? (
Video Solution
Solution: a.
Details:

(Video Source | Transcript)
)
a. Minutes (min)
b. Pounds (lbs)
c. Dollars (\$)
d. Centimeters (cm)
6. Which of the following units are used to measure weight? (
Video Solution
Solution: d.
Details:

(Video Source | Transcript)
)
a. Seconds (sec)
b. Kelvin (K)
c. Feet (ft)
d. Pounds (lbs)

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