Moa mystery
This is a level 3 geometry activity from the Figure It Out theme series. This is focused on using scale factors from a diagram to calculate length and drawing an enlargement. A PDF of the student activity is included.
About this resource
Figure It Out is a series of 80 books published between 1999 and 2009 to support teaching and learning in New Zealand classrooms.
This resource provides the teachers' notes and answers for one activity from the Figure It Out series. A printable PDF of the student activity can be downloaded from the materials that come with this resource.
Specific learning outcomes:
- Use scale factors from a diagram to calculate length.
- Draw an enlargement.
Moa mystery
Achievement objectives
GM3-6: Describe the transformations (reflection, rotation, translation, or enlargement) that have mapped one object onto another.
Required materials
- Figure It Out, Level 3, Theme: At Camp, "Moa mystery", page 22
- metre rulers, chalk
- a classmate
See Materials that come with this resource to download:
- Moa mystery activity (.pdf)
Activity
In this activity, students will be applying techniques that are used by forensic scientists to estimate the size of people and animals. They will be using ratio or proportion.
Students will first need to calculate what part of the moa’s height was taken up by the thigh bone. In the scale drawing of the moa, the thigh bone measures 69 millimetres.
The moa’s height in the drawing is 153 millimetres. Generally, moa were over twice as tall as the length of their thigh bones, but 153 ÷ 69 = 2.22 is a more accurate scale factor for this activity.
The thigh bone found during the caving expedition is 110 centimetres long, so the moa’s height would have been 110 x 2.22 = 244 centimetres or 2.44 metres.
Challenge students to work out how long the other major bones of the moa would have been, given the size of the thigh bone. They will need this information if they are to draw the life-size moa skeleton on the concrete or on paper.
Students will need to work out what fraction of 110 centimetres each bone is.
For example,
- The lower leg bone is 30 millimetres long in the picture, and therefore it is less than half the 69 millimetre length of the thigh bone.
- 30 ÷ 69 = 0.435 gives the scale factor. 0.435 x 110 cm = 47.9 cm gives the actual real-life length of this moa’s lower leg bone.
Students may measure the moa as it stands in the illustration. The moa in the illustration is approximately 153 mm from its head to the ground. So its actual height would have been 153 ÷ 69 x 110 = 244 cm (2.44 m). Students could discuss whether the moa raised its head higher on occasions.
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