## Thursday, December 2, 2010

### Mary Jane's Scribepost for December 2, 2010

Hello Everyone! For today's math class, we first had to double the so called "carlos" diagram using tangram shapes. We then went on with talking about dilation and reduction.

Dilation: an enlargement of an object, shape or design. (my own definition, feel free to correct me)

For example:

We also talked about scale factors and scales (ratios).

Scale Factor: The constant factor by which all dimensions of an object are enlarged or reduced in a scale drawing.

Diagram above: It shows the enlargement and the reduction of the square. When the square is enlarged, the area will increase from 36 units(squared) to 144 units(squared) and the side length will increase from 6 units to 12 units. In this case you are what is called doubling (multiplying by 2) and the scale factor is 2. The scale for the enlargement will be 1:2. When the square is reduced, you are basically multiplying the bigger square by 1/2 or 0.5. In this case you are halving and the scale factor is 1/2 or 0.5. The scale for the reduction will be 2:1.

Don't forget to do:

Chapter 4.1 (Page 130-135)
Show You Know (page 132 & 134)