Percentages_Presentation.pptxpoiugfvjhjuhyft

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1. Percentages Understanding the concept of percentage and solving percent problems

2. Learning Objectives • Describe the meaning of percentage • Identify the amount in a percent problem • Identify the base in a percent problem • Identify the percent in a percent problem • Find the unknown quantity (amount, base, or percent) in a percent problem

3. What is a Percentage? • A percentage is the top part of a fraction whose bottom part is 100. • Percentages are useful because they make it easy to compare things. Examples: - 50% means one-half (50/100) - 25% means one-quarter (25/100)

4. Example: Comparing Marks I got 24/30 in the first exam and 36/60 in the second. To compare: 24/30 (100) = 80% 36/60 (100) = 60% So, I did better in the first exam.

5. The Three Parts of a Percent Problem • Base – the whole • Amount – a part of the whole • Percent (or rate) – the ratio of amount to base, expressed as a percent

6. Formulas for Percent Problems Percent = (Amount / Base) × 100 Base = (Amount × 100) / Percent Amount = (Percent × Base) / 100

7. Example Calculation Find 20% of 800: Here: Base = 800 Percent = 20% Amount =

8. Practice Problems 1. 21 is 70% of what number? 2. 36 is 60% of 60. Identify base, amount, percent. 3. Find the percent: 15 is what percent of 60?

9. Practice Problems 4. Complete the table: Amount | Base | Percent -------|------|-------- 30 | 90 | ? 80 | 15 | ? 25 | 40 | ?