Welcome to our tutorial on understanding percents, a key aspect of our section on 'Ratios in Percents'. In this tutorial, we'll demystify the concept of percents and show you their intimate relationship with ratios.

The term 'percent' comes from the Latin 'per centum', which means 'by the hundred'. A percent is essentially a ratio that compares a number to one hundred. Hence, the concept of percentages and ratios are inherently linked.

## The History of Percentages

The use of percentages and the concept of expressing values out of a hundred has been traced back to Ancient Rome. However, it was the mathematician and astronomer, Ptolemy, who made a significant contribution to their usage in the 2nd century AD. He used an early form of decimal points and percentages in his work, establishing the foundations for our modern mathematical understanding.

## How are Percents related to Ratios?

Percents are, in essence, a specific type of ratio. They express a relationship between a part and a whole, where the whole is always 100. If we say, for example, '50%', we mean '50 out of 100', or the fraction 50/100. This is a simplifiable ratio, equivalent to 1:2 or 1/2 as a fraction.

= 1/2 (as a fraction)

= 1:2 (as a ratio)

## Expressing Ratios as Percentages

Converting a ratio to a percentage is a straightforward process. You simply divide the 'part' by the 'whole' and then multiply the result by 100.

3 ÷ 7 × 100 = 42.85%

## Expressing Percentages as Ratios

Conversely, to convert a percentage back into a ratio, you convert the percentage to a fraction of 100, then simplify the fraction to its simplest form. If we take our earlier example of 42.85%, we can express this as a ratio:

= 3/7 (as a fraction)

= 3:7 (as a ratio)

## Real-Life Applications of Percentages

Percentages find extensive use in a variety of fields, including finance, statistics, and data analysis. Understanding percentages is crucial in everyday scenarios, such as calculating discounts, understanding interest rates, or interpreting statistical data.

For instance, if a shop offers a 20% discount on an item, you can calculate the discount amount by finding 20% of the item's price. Similarly, if a bank offers a 2% annual interest rate, you can determine how much your savings would grow over a year by calculating 2% of your saved amount.

## Practice Converting Between Ratios and Percentages

Now that we've covered the theoretical aspects, it's time for some practice! Try converting the following ratios to percentages and vice versa.

- Ratio to Percent: 5:15, 2:3, 7:21
- Percent to Ratio: 75%, 66.67%, 33.33%

Remember, the key to mastering percentages, like any other mathematical concept, is practice. So, keep practicing, and percentages will soon become second nature to you.

## Conclusion

We hope this tutorial has helped you understand the concept of percentages and their relationship with ratios. In the next section, we'll dive deeper into the fascinating world of percentages and explore more complex applications. Stay tuned!

## Ratios in Percents Tutorials

If you found this ratio information useful then you will likely enjoy the other ratio lessons and tutorials in this section:

- Understanding Percents
- How to Convert Ratios to Percents and Vice Versa
- Exercises to Reinforce Your Understanding

**Next:** Ratios and Rates