**Learning Intention: **Students will understand how to calculate and simplify ratios using body measurements as an example.

**Success Criteria: **Students will be able to correctly estimate the ratio of various body proportions, using average class data.

Do you think that “Barbie” dolls portray a realistic image of a human figure? What about “Bratz” dolls and Manga figures? What is it about these figures that make them so appealing to children? We are going to investigate the proportions of “Barbie” dolls and other figures to compare their ratios with the average year 7 student from Hawkesdale college. We now have the data that gives us some average measurements of height, head circumference, arm and leg length and chest, waist and hip measurements of the average student in our class.

- As you can see from the figure above, “Barbie” has a head to height ratio of 4 to 28cm or 1:7.
- Her leg to height ratio is 14cm to 28cm or 1:2.
- Her neck to height ratio is 2cm to 28cm or 1:14.
- Her head circumference is larger than her waist circumference.
- Her foot length to leg length is 2cm to 14cm, so, 1:7.

Calculate the same ratios for the average Year 7 student, using our data. What can you conclude?

Bill Genereux has written a terrific post about the proportions of superheroes, from a book that teaches people how to draw comic book heroes. Malyn Mawby has also written a great post about using Da Vinci’s “Vitruvian Man” to learn about ratio and proportion.