Tuesday, November 28, 2006
posted by Alanna at 4:22 p.m.
Today in class, we started working on SIMILAR FIGURES. We also worked on SURFACE AREA and VOLUME.

*REMINDER: The quiz is moved to tomorrow!*

Class was started off today with Ms. Armstrong drawing a little man on the board...

In the second picture, the length and the width has been doubled. Does that mean that we have doubled the size of the whole picture? Not quite, because we have doubled BOTH the length and the width, the size is actually quadrupled.
Next, instead of doing the rest of the notes, we did a worksheet on area and volume...
We had to find the surface area and volume of 2 cubes. I have tried to upload them, but it is not working, so the first cube was Length=2, width=2, depth=2. The second cube was length=6, width=6 and depth=6.
1) Surface area: 6(LW)
=24cm2
Volume: 2x2x2
=8cm3
2)Surface Area: 6(LW)
=216cm2
Volume: 6x6x6
=216cm3
The next part of the sheet was:
How many times bigger are the sides in the bigger cube? 3
*NOTE: when it says side, it means length of a side, not the whole side.*
How many times bigger is the surface area of the bigger cube compared to the smaller one?
9 times or 32
How many times bigger is the volume of the bigger cube compared to the smaller one?
27 times or 33
HINT: notice that when change change the answer into an exponent, the exponent for surface area is 2, and the exponent for volume is 3.
That's what we did for this sheet. The other side we have for homework.
Okay, now to continue on with some more notes:
To find the "new area or volume"
area= (scale factor)2x(old area)
volume=(scale factor)3x(old volume)
ex. The area of a region is 10cm2
by what factor must each dimension be multiplied to increase the area by 20cm2?
New area is 20+10=30cm2
30cm2=k2(10)
30 k2(10)
__= ____
10 10
3=k2 square root of 3=k
wow... okay, thats it for what we did in class today. Sorry about the pictures, it wasn't working very well. I hope this helped anyway though.
HOMEWORK!
finish the other side of the worksheet
exercise #24
STUDY! There's a quiz TOMORROW!