6.1+Scaling+Up+or+Down+0910

ABP 11-21-09 Math 7


 * BIG IDEA:** Many important practical and mathematical applications involve comparing quantities of one kind or another; it is important to know which method to use and how we should use them.


 * ESSENTIAL QUESTION:** What methods are there for comparing things?

__ 6.1 __ – __Scaling Up or Down__ __ Notes __ : Some examples of comparisons someone in elementary school would understand are: // Five small books would **fit into** one large book. // // The large chocolate bar is three **times** the size of the small chocolate bar. //
 * Scale Factor – ** The number used to multiply the coordinates of a figure to stretch or shrink it.

__ Problem 6.1 __
 * // T.rex //**** weighed about 8,100 kilograms and reached heights of up to 6 meters – almost as tall as a two-story house! Archeologists have uncovered //T.rex// skulls 1 meter long and //T.rex// incisors (the longest teeth) 15 centimeters long. **


 * A “larger than average human being can be about 2 meters tall and weigh 90 kilograms. Human incisors are about 1 centimeter long, and a large human skull can be about 20 centimeters long. **
 * How big was //T.rex// compared to a “larger than average” human being? **
 * Write a paragraph to help someone younger than you understand how the size of //T.rex// compares to the size of a human. Be very specific about the comparisons you are making. **

T.rex’s were much larger than humans. For example, about fifteen human incisors would fit into one T.rex incisor. Also, the T.rex skulls were five times the size of human skulls! Third, T.rex were three times taller a “larger than average” human. And lastly, the weight of a T.rex is equal to the weight of ninety “larger than average” human beings! So, in conclusion, A T.rex is like a giant to a human.

__ 6.1 Follow-Up __ ANS: The scale factor between a grown T.rex and an infant T.rex would be the same as the scale factor between a grown T.rex and a human. 2. **  How long were the incisors of this young //T.rex//? **   ANS: The incisors of this young T.rex were one centimeter long. 3. **  How long was the skull of this young //T.rex//? **   ANS: The skull of this young T.rex was about 20 centimeters.
 * 1. Suppose an infant //T.rex// was the same height as the human described in the problem and was similar to an adult //T.rex//. What would be the scale factor between a grown //T.rex// and the infant //T.rex//? **