Ratios

• What does a ratio compare?

  Values
• What does a ratio indicate about two things?

  How much of one thing compared to another
• What is a part-to-part ratio?

  • Compares one part to another part
  • Example: 3 squares to 1 circle
  • Can be expressed as 3:1 or 3 to 1
• How can ratios be shown?

  Using “ : “ to separate values
• If a part-to-part ratio is 6:2, what is the scaled-up version of the ratio?

  3:1
• What is a part-to-whole ratio?

  • Compares a part to the whole
  • Example: 5 dogs, 2 boys, 3 girls
  • Ratios: boys to all dogs is 2:5, girls to all dogs is 3:5
• What is the part-to-part ratio of boys to girls in 5 dogs with 2 boys and 3 girls?

  2:3
• What is the part-to-whole ratio of girls to all dogs?

  3:5
• How can the ratio of boys to girls also be expressed?

  As 3:2 or $\frac{3}{2}$
• What is the relationship between scaling ratios?

  Always multiply or divide by the same value
• What are the key differences between part-to-part and part-to-whole ratios?

  • Part-to-part: compares one part to another part
  • Part-to-whole: compares a part to the entire group
  • Examples provided for both types