Ratios and proportions

• Ratio


  Compares two or more quantities or numbers and shows the relationship between them
• Writing ratios


  1. Using a colon

  2. Fractional form

  3. Using the word "to"
• Order of quantities in a ratio

  Order matters
• Part-to-part ratio


  Compares part of the group to another part of the group
• Part-to-whole ratio


  Compares part of the group to the whole group
• Ratios can be simplified, just like fractions
• Solving a proportion using cross multiplication

  1. Draw arrows to represent cross multiplication

  2. Multiply the two values on one side

  3. Equate the result to the multiplication of the two values on the other side

  4. Isolate the missing variable by dividing both sides
• Proportion


  Two ratios that are equivalent, with a missing value represented by a variable