Ratio, Rate and Percent
Ratio, Rate and Percent - Unit Review
1. Ratio
a. Definition – A comparison of two or more numbers
b. Can be written three ways
i. Words, ie 5 to 7
ii. With a colon, ie 5:7
iii. As a fraction 5/7
c. A ratio is in lowest terms when the GCF of both numbers is 1
d. A proportionate ratio is a number sentence that shows two equal ratios (Equivalent Ratios is more than two)
e. You can make proportions or find proportions by by using a scale factor and x or dividing both terms by the same number
f. Each number in a ratio is called a term and you can compare two or more numbers.
g. Ratios can compare:
i. Part of a group to another group
ii. Part of a group to the whole group
iii. Whole group to part of a group
2. Rate
a. Definition – a comparison of 2 numbers with different units
b. A rate is usually written as a unit rate where the second term is 1 or base of 10.
c. You write a rate using a backslash,’/’ which means ‘per’.
d. Comparing Unit Rates
i. To ensure you are comparing apples to apples always get a rate into it’s unit rate.
ii. Ie: Which is the better deal? See Sheet
3. Fractions and Decimals as Percents
a. A percent is always out of 100
b. A fraction can be expressed as a percent by converting it to a fraction with a denominator of 100.
c. A decimal can be expressed as a % by multiplying it by 100.
d. Do a Chart to review
4. Solving Percent Problems
a. Percent is used everyday in so many applications. Taxes, sales, discounts, and commission.
b. You can find the % of a number by multiplying.
c. “Of” in math means ‘multiply’.
d. You find the % and add it to the whole or multiply the total by 1.tax.
e. Commission – you make a % of what you sold.
5. Cross Multiplying
a. You can solve any proportion (%, rate or ratio) by using cross multiplication.
b. It is a method of solving for an unknown quantity in a proportion.
c. You must ensure the numerators of both proportions are representing the same quantity.
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