1. Lesson 6

Mathematics 20-2 Module 6 Lesson 6

Module 6: Proportional Reasoning

 

Lesson 6: Scale Factors and Areas of 2-D Shapes

 
Focus

 

This is an image of a bobblehead doll. Its head is not in proportion to the size of its body.

Have you ever noticed how some cartoon characters or figurines have heads that seem much bigger than the rest of their bodies? Bratz dolls, bobblehead dolls, and some cartoon characters, such as Betty Boop, are all examples of characters with heads that are not in proportion to the size of their bodies. Can you think of other examples of a character, doll, or figurine with a head that is oversized (or undersized) compared to the rest of its body?

 

In cartoons, large heads do not always mean the character has a large ego! The disproportionately large heads take up a larger area in the cartoon and make the characters stand out. Unlike cartoons, scale diagrams require dimensions and areas that are proportional. This ensures that the enlarged or reduced shapes are similar to the original ones.

 

This lesson will help you answer the following critical questions:

  • When a shape is enlarged or reduced, what is the relationship between scale factor and a shape’s dimensions?
  • When a shape is enlarged or reduced, what is the relationship between scale factor and a shape’s area?
Assessment
  • Math Lab: Scale Factors and Areas of 2-D Shapes

All assessment items you encounter need to be placed in your course folder.

 

Materials and Equipment
  • calculator
  • ruler
Did You Know?

There are companies that specialize in creating custom, personalized bobblehead dolls. You can get your own personal bobblehead cake topper or cellphone holder! Your bobblehead can even have its own motorbike, golf club, or furniture. How do you think the bobblehead creators ensure that the bobblehead looks like you? Is there a standard ratio between the size of the body and the size of the head that makes the figure a bobblehead?