Mastering the constant of proportionality is a fundamental concept in mathematics, especially for 7th-grade students. Understanding this concept opens up avenues for various mathematical applications in real life, from figuring out ratios to understanding direct relationships in functions. This article will delve into the constant of proportionality, its significance, how to calculate it, and offer a sample worksheet for practice.
Understanding Proportionality
What is Proportionality? π€
Proportionality refers to a relationship between two quantities where the ratio of one quantity to another remains constant. For instance, if you have two quantities (y) and (x), they are proportional if:
[ \frac{y}{x} = k ]
Here, (k) is known as the constant of proportionality.
Real-Life Examples of Proportionality π
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Recipe Adjustments: If a recipe for cookies calls for 2 cups of sugar to make 24 cookies, then to make 48 cookies, you would need 4 cups of sugar. The ratio of sugar to cookies remains constant at ( \frac{2}{24} = \frac{4}{48} = \frac{1}{12} ).
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Speed and Distance: If you travel 60 miles in 1 hour, your speed is consistent. If you travel for 2 hours at the same speed, you will cover 120 miles, maintaining a constant ratio of distance to time.
Finding the Constant of Proportionality
To find the constant of proportionality, follow these steps:
- Identify the quantities you are comparing.
- Create a ratio of the two quantities.
- Simplify the ratio, if necessary.
Example Problem:
Letβs say a car travels 150 miles in 3 hours. To find the constant of proportionality (speed):
[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{150 \text{ miles}}{3 \text{ hours}} = 50 \text{ miles per hour} ]
In this case, (k = 50).
Worksheets and Practice Problems π
To master the constant of proportionality, practice is essential. Below is a worksheet template that educators can use for 7th-grade students.
Worksheet on Constant of Proportionality
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If (y) is proportional to (x) and (y = 24) when (x = 6), find (k).
Solution:
- [ k = \frac{y}{x} = \frac{24}{6} = 4 ]
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A car consumes 10 gallons of gas to travel 250 miles. Find the constant of proportionality for miles per gallon.
Solution:
- [ k = \frac{250 \text{ miles}}{10 \text{ gallons}} = 25 \text{ miles per gallon} ]
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If a child can read 12 pages in an hour, how many pages can they read in 5 hours?
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A machine produces 150 widgets in 3 hours. Calculate how many widgets it would produce in 8 hours.
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Create a table showing the relationship between hours worked and pay earned if someone earns $15 per hour.
<table> <tr> <th>Hours Worked (x)</th> <th>Pay Earned (y)</th> </tr> <tr> <td>1</td> <td>$15</td> </tr> <tr> <td>2</td> <td>$30</td> </tr> <tr> <td>3</td> <td>$45</td> </tr> <tr> <td>4</td> <td>$60</td> </tr> <tr> <td>5</td> <td>$75</td> </tr> </table>
Important Notes
"To verify if two quantities are proportional, simply check if the ratios between corresponding values remain constant."
Conclusion
Mastering the constant of proportionality is a pivotal skill for 7th-grade students, serving as a foundational building block for more advanced mathematical concepts. Through real-life examples and consistent practice using worksheets, students can develop a deeper understanding and appreciation for this mathematical principle. By engaging with the content in both practical and theoretical contexts, learners can enhance their mathematical skills effectively.