Finding a percentage increase

Oct 13, 2025 by wbrum.org 141 views

Calculating Percentages in Mathematics

In mathematics, percentages are a way to express a value as a fraction of 100. To find a percentage, we need to divide the value by the total and multiply by 100. In this case, we are asked to find what percent 21 is of 28.

Understanding the Problem

To solve this problem, we need to follow the order of operations: divide, multiply, and then find the percentage. The problem can be broken down into the following steps:

Divide 21 by 28 to find the fraction.
Multiply the fraction by 100 to find the percentage.

Step 1: Divide 21 by 28

To divide 21 by 28, we can use long division or a calculator. The result of the division is:

21 ÷ 28 = 0.75

Step 2: Multiply the Fraction by 100

Now that we have the fraction 0.75, we can multiply it by 100 to find the percentage:

0.75 × 100 = 75%

Conclusion

Therefore, 21 is 75% of 28.

Real-World Applications of Percentages

Percentages are used in many real-world applications, such as:

Finance: Percentages are used to calculate interest rates, investment returns, and credit card balances.
Science: Percentages are used to express the concentration of a solution, the amount of a substance in a mixture, and the accuracy of a measurement.
Business: Percentages are used to calculate profit margins, sales growth, and employee productivity.

Importance of Percentages in Everyday Life

Percentages are an essential part of everyday life. We use them to make informed decisions about our finances, health, and well-being. For example, when shopping for a product, we may compare the prices of different brands and choose the one with the lowest price. This requires us to calculate percentages to determine the savings.

Calculating Percentages in Real-World Scenarios

Let's consider a real-world scenario where we need to calculate a percentage:

Scenario: A company has a sales growth of 25% over the past year. If the company had sales of $100,000 last year, how much did they make this year?

To solve this problem, we need to multiply the sales growth by the original sales amount:

25% × $100,000 = 0.25 × $100,000 = $25,000

Therefore, the company made $25,000 in sales growth this year.

Tips for Calculating Percentages

Here are some tips for calculating percentages:

Use a calculator: Calculators can help you quickly calculate percentages and avoid errors.
Break down the problem: Break down the problem into smaller steps to make it easier to solve.
Check your work: Check your work to ensure that you have the correct answer.

Common Percentage Calculations

Here are some common percentage calculations:

Finding a percentage: To find a percentage, divide the value by the total and multiply by 100.
Finding a value: To find a value, divide the percentage by 100 and multiply by the total.
Finding a percentage increase: To find a percentage increase, subtract the original value from the new value and divide by the original value.

Conclusion

In conclusion, calculating percentages is an essential skill in mathematics. By following the order of operations and using real-world examples, we can make informed decisions about our finances, health, and well-being. Remember to use a calculator, break down the problem, and check your work to ensure that you have the correct answer.

Final Answer

The final answer is: 75%

Calculating Percentages in Mathematics

Understanding the Problem

To solve this problem, we need to follow the order of operations: divide, multiply, and then find the percentage. The problem can be broken down into the following steps:

Divide 21 by 28 to find the fraction.
Multiply the fraction by 100 to find the percentage.

Step 1: Divide 21 by 28

To divide 21 by 28, we can use long division or a calculator. The result of the division is:

21 ÷ 28 = 0.75

Step 2: Multiply the Fraction by 100

Now that we have the fraction 0.75, we can multiply it by 100 to find the percentage:

0.75 × 100 = 75%

Conclusion

Therefore, 21 is 75% of 28.

Real-World Applications of Percentages

Percentages are used in many real-world applications, such as:

Finance: Percentages are used to calculate interest rates, investment returns, and credit card balances.
Science: Percentages are used to express the concentration of a solution, the amount of a substance in a mixture, and the accuracy of a measurement.
Business: Percentages are used to calculate profit margins, sales growth, and employee productivity.

Importance of Percentages in Everyday Life

Calculating Percentages in Real-World Scenarios

Let's consider a real-world scenario where we need to calculate a percentage:

Scenario: A company has a sales growth of 25% over the past year. If the company had sales of $100,000 last year, how much did they make this year?

To solve this problem, we need to multiply the sales growth by the original sales amount:

25% × $100,000 = 0.25 × $100,000 = $25,000

Therefore, the company made $25,000 in sales growth this year.

Tips for Calculating Percentages

Here are some tips for calculating percentages:

Use a calculator: Calculators can help you quickly calculate percentages and avoid errors.
Break down the problem: Break down the problem into smaller steps to make it easier to solve.
Check your work: Check your work to ensure that you have the correct answer.

Common Percentage Calculations

Here are some common percentage calculations:

Finding a percentage: To find a percentage, divide the value by the total and multiply by 100.
Finding a value: To find a value, divide the percentage by 100 and multiply by the total.
Finding a percentage increase: To find a percentage increase, subtract the original value from the new value and divide by the original value.

Q&A: Calculating Percentages

Q: What is the formula for calculating a percentage?

A: The formula for calculating a percentage is: (value ÷ total) × 100.

Q: How do I calculate a percentage increase?

A: To calculate a percentage increase, subtract the original value from the new value and divide by the original value. Then, multiply by 100 to find the percentage.

Q: What is the difference between a percentage and a fraction?

A: A percentage is a way to express a value as a fraction of 100, while a fraction is a way to express a value as a part of a whole.

Q: Can I use a calculator to calculate percentages?

A: Yes, you can use a calculator to calculate percentages. In fact, calculators can help you quickly calculate percentages and avoid errors.

Q: How do I check my work when calculating percentages?

A: To check your work, make sure that you have followed the order of operations and that your answer is reasonable. You can also use a calculator to double-check your answer.

Q: What are some common percentage calculations?

A: Some common percentage calculations include finding a percentage, finding a value, and finding a percentage increase.

Q: Why are percentages important in everyday life?

A: Percentages are important in everyday life because they help us make informed decisions about our finances, health, and well-being. We use percentages to compare prices, calculate interest rates, and determine the accuracy of a measurement.

Conclusion

Final Answer

The final answer is: 75%