Finding percentages is a common task in many areas of life, from calculating discounts to determining grades. This article will show you how to easily calculate what 70% of 120 is, and provide some helpful tips for solving similar problems.
Understanding Percentages
Before we dive into the calculation, let's quickly review what percentages represent. A percentage is a fraction out of 100. So, 70% means 70 out of 100, or 70/100.
Method 1: Using Decimal Conversion
This is arguably the easiest method. We convert the percentage to a decimal and then multiply it by the number.
Step 1: Convert the percentage to a decimal.
To convert 70% to a decimal, divide 70 by 100:
70 ÷ 100 = 0.70
Step 2: Multiply the decimal by the number.
Now, multiply the decimal (0.70) by 120:
0.70 x 120 = 84
Therefore, 70% of 120 is .
Method 2: Using Fractions
This method involves converting the percentage to a fraction and then simplifying before multiplying.
Step 1: Convert the percentage to a fraction.
70% can be written as the fraction 70/100.
Step 2: Simplify the fraction (if possible).
Both 70 and 100 are divisible by 10, simplifying the fraction to 7/10.
Step 3: Multiply the fraction by the number.
Now, multiply the simplified fraction (7/10) by 120:
(7/10) x 120 = (7 x 120) / 10 = 840 / 10 = 84
Again, we find that 70% of 120 is .
Method 3: Proportion Method
This method sets up a proportion to solve for the unknown value.
Step 1: Set up a proportion.
We can set up a proportion like this:
70/100 = x/120
where 'x' represents the value we want to find (70% of 120).
Step 2: Cross-multiply.
Cross-multiplying gives us:
70 x 120 = 100 x
Step 3: Solve for x.
8400 = 100x
x = 8400 / 100
x = 84
Once again, we arrive at the answer: 70% of 120 is .
Practical Applications
Understanding how to calculate percentages is crucial in various real-world scenarios:
- Sales and discounts: Calculating the final price after a discount.
- Taxes: Determining the amount of tax on a purchase.
- Grades and scores: Converting raw scores to percentages.
- Statistics: Analyzing data and interpreting results.
Conclusion
Calculating percentages is a fundamental mathematical skill. Whether you use the decimal, fraction, or proportion method, the answer remains the same: 70% of 120 is 84. Choose the method that you find most comfortable and apply it to solve similar percentage problems. Remember to practice regularly to master this important skill!
