Karra's Scribe Post for November 4, 2010

2.2 - Text Book
Question: #16

Bella is more comfortable working with integers than with positive and negative decimal numbers. This is her way of understanding -4.3 + 2.5 .

-4.3 is -43/10 or -43 tenths

2.5 is 25/10 or 25 tenths

-43 tenths + 25 tenths is -18 tenths

-18 tenths is -18/10 or -1.8

So, -4.3 + 2.5 = 1.8

A ) Use Bella's method to determine 6.1 + (-3.9).

B) How could you modify Bella's method to determine 1.25 -3.46?

Karra's Scribepost for October 8th

On Friday Backe went over the homework we were supposed to do .

d/2 =r

30/2 = 15

Small Cylinder

2 pi r h

2 pi (15)(40) = 1200 pi

= 3769.91 cm squared


















Big Cylinder

d/2 =r
50/2 = 25

2 pi r h =2 pi (25)(90)

= 4500 pi

= 14137.17 cm squared

Big circle - Small circle

pi r squared -pi r squared

pi 25 squared - pi 15 squared

pi 625 - pi 225 = pi 400

1963.50- 706.86 =

1256.63 cm squared

TSA =3769.91+1256.63+14137.17= 19163.71 cm squared

Nearest hundredth of a meter
Find the surface Area

Large Small
d/2 = r d/2 =r
2.75/2 = 1.38 1/2 = 1

d = 1 m
d = 2.75 cm

2(Big circle - small circle ) Big outside - Small outside
2( pi r squared - pi r squared) 2 pi r h =2 pi r h
2(pi 1.375 squared - pi 0.5 squared ) 2 pi 1.375(5) = 2 pi 0.5 (5)
2(pi 1.89 - pi 0.25) 13.75 pi = 5 pi

2(pi 1.64) 18.75 pi

=3.28 58.90 m squared

10.30 m squared




Circles +outside and inside
TSA = 10.30 + 58.90 =
= 69.20 m squared

HOMEWORK !! WOO :D
Backe's collecting the self evaluation and the Foldable - Surface area formula and symmetry use magazine or draw
Workbook- Vocabulary Link + Chapter Review + Textbook Chapter test only Surface Area
If not getting understanding surface area do extra practice sheet test.





That's ALL the homework :D

& I picckkkk.... RAQUEL to do the next scribe post :D have fun (:


sorry I couldn't make the symbols .