Ratios, Proportions, and Percentages for HESI A2 Math
Ratios and percentages appear in many everyday mathematical situations. Understanding the relationship between quantities can help you solve a wide variety of HESI A2 Math questions.
Understanding Ratios
A ratio compares two quantities. For example: 2 nurses to 5 patients can be written as: 2:5 It can also be represented as: 2/5
Simplifying Ratios
Suppose a class has 12 students wearing blue shirts and 8 wearing white shirts. The ratio of blue to white is: 12:8 Both numbers can be divided by 4: 3:2 So the simplified ratio is 3:2
What Is a Proportion?
proportion states that two ratios are equal. For example: 2/3 = 4/6 Both fractions represent the same relationship. You can solve many proportion problems by cross multiplication. Example Suppose: x/5 = 6/10 Cross multiply: 10x = 30 Then: x = 3
Percentages
A percentage represents a quantity out of 100. For example: 25% = 25/100 = 0.25 To convert a percentage to a decimal, divide by 100.
Finding a Percentage of a Number
Suppose you need to find 20% of 80. Convert 20% to a decimal: 0.20 Then: 0.20 × 80 = 16 Therefore, 20% of 80 is 16.
Check Your Units
When solving word problems, make sure the quantities are being compared correctly. A ratio involving minutes and hours, for example, may require a conversion before you can compare the numbers.
Final Takeaway
Practice moving between ratios, proportions, fractions, decimals, and percentages. These relationships become much easier when you write out each step rather than trying to solve everything mentally.
