6.1+Scaling+Up+or+Down+1011


 * Chae Un Ok**
 * Jan. 25th 2010**
 * Math 7B**

==**The Big Idea **==

Many impartant practical and mathematical applications involve comparing quantities of one kind or another; it is impoartant to know which method to use and how we should use them.

** Essential question **

Which comparing strategies work best in which situations?



6.1

**Write a paragraph to help someone younger than you understand how the size of the T-Rex compares to the size of a human. Be very specific about the comparisons you are making. ** T-Rex is 6 meters tall. You are about 1 meter tall. So a T-Rex is as tall as 6 of you. A T-Rex weighs 8100 kg. You weigh around 30 kg. So, a T-Rex is as heavy as 270 of you. That is, there has to be 270 of you to weigh as heavy as a T-Rex.

Now, a "larger than average" human being is 2 meters tall. So a T-Rex is as tall as 3 of average human beings. Most human beings are 80 kg average. So a T-Rex is as heavy as almost 100 of you. Do you now understand, how big a T-Rex is?

6.1 Follow-Up

** 1. Suppose an infant T-Rex was the same height as the human described in this problem and was similar to an adult T-Rex. What would be the scale factor between a grown T-Rex and an infant T-Rex? ** The scale factor between a grown T-Rex and an infant T-Rex would be 3:1. The infant T-Rex will be 1/3 of an adult T-Rex.

** 2. How long were the incisors of this young T-Rex? ** The incisors of this young T-Rex would be 1/3 of 15 cm. The young T-Rex's incisors would be 5 cm.

** 3. How long was the skull of this young T-Rex? ** The length of the skull of this young T-Rex would be 1/3 of 1 m. Its skull would be around 33cm.