Question

List three units for length and give one example for each (i.e., list an object and its length expressed in that unit).

Short answer

Metric examples: 0.76 mm (thickness of a credit card), 2.4 cm (diameter of a quarter), 1 m (length of a guitar). Non-metric examples: 7.5 in (length of a pencil), 6.5 ft (height of a door), 3 yd (length of a small car).

Step-by-step solution

Identify Metric Units of Length

Identify common metric units of length used in measurements. These can include the millimeter (mm), centimeter (cm), and meter (m).

Provide Examples for Each Unit

Provide examples of objects with their length expressed in each of the identified units. For a millimeter, consider the thickness of a credit card which is about 0.76 mm. For a centimeter, think about the diameter of a quarter which is approximately 2.4 cm. Lastly, for a meter, consider a guitar which often has a length around 1 m.

List Non-Metric Units of Length

Non-metric units can also be used as examples. Common non-metric units include the inch (in), foot (ft), and yard (yd).

Provide Examples for Each Non-Metric Unit

As examples for non-metric units, a standard pencil is roughly 7.5 in long, the height of a door is commonly around 6.5 ft, and the length of a small car might be about 3 yd.

Key concepts

Metric Units of Length

Understanding the metric system is crucial for measuring lengths accurately and universally. The metric system is an international standard of measurement based on multiples of ten, which makes it very easy to convert between different units. For example, when dealing with smaller objects or precise measurements, we commonly use millimeters (mm). This is the unit you would use to measure something as thin as a credit card, which is approximately 0.76 mm thick.

Moving up in scale, we have the slightly larger centimeter (cm), which is ideal for objects like a coin. For instance, the diameter of a quarter is about 2.4 cm. And when we're measuring something larger, like the length of a piece of furniture or musical equipment, we switch to meters (m). Consider a guitar, a familiar and relatable item, which is often about 1 meter long. Each leap from millimeters to centimeters to meters represents a multiplication by ten, illustrating the simplicity and efficiency of the metric system.

Non-Metric Units of Length

While the metric system is widely used around the world, the non-metric units of length are still prevalent, especially in the United States. These units include the inch (in), the foot (ft), and the yard (yd).

Understanding Inches

An inch can be considered when measuring smaller objects such as a standard pencil, which is about 7.5 inches long. This unit is handy for everyday measurements and is often found on rulers and tape measures.

Feet for Mid-sized Measurements

Feet, on the other hand, become useful when measuring things like furniture or rooms. A door's height is a good example, with a typical measurement of around 6.5 feet.

Yards for Larger Distances

Yards are suitable for even larger dimensions, say, when measuring the length of certain vehicles. As an illustration, a small car may be about 3 yards long. Learning when and how to use these traditional units remains essential for understanding length measurements in certain contexts and countries.

Measurement Examples

To solidify your understanding of units of length, let's look at some practical measurement examples you might encounter in everyday life.

• The width of a smartphone might be around 7 cm or 2.75 inches, depending on whether you're using metric or non-metric units.
• The distance from one city to another is often measured in kilometers or miles. For instance, you might say that it's about 100 km (or approximately 62 miles) between two particular cities.
• When baking, you could be required to roll out the dough to a thickness of 5 mm, a very precise measurement that highlights the utility of smaller metric units.

Whether you’re cooking, traveling, or engaging in some DIY home improvement, being versed in both metric and non-metric units can greatly enhance your understanding of space and proportions. The key is to select the right unit that matches the scale of the object or distance you are measuring, ensuring accuracy and understandability.