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 .

John's Scribe Post Part 2

So the second part is the cylinder on page 31 were we had to calculate the area so in the picture below shows you the Diameter and radius:
This is what the cylinder looks like spread out, this is the out side of the cylinder.

This is the inside of the cylinder.

Then Mr.Backe wrote this down 

2(pie r² big-pie r² small)

 2(pie 10² - pie 5²)

                                                                                  2(pie 5²)
                                                                                  2(pie)(25) 

                                                                                  = 157.1

so thats it I think if anything is wrong tell me because I have to fix it.

Homework is TUTPUP, Apply and Practise 4-9 

-John! and I pick Paulo for the next scribepost.

John's Scribe Post for October 4th, 2010

Sup guys so today in math class Mr.Backe asked us if we did Check Your Understanding on page 31. No one did it so we did the problem together. First Mr.Backe drew the cake like this one:

So Mr.Backe told us to draw the top view. Then he asked me what happens to the circle on top. So I said that it blends in with the square part of the cake.

Then we had to draw the side view which is the one you see in the bottom picture:

So the reason why I have 20 cm d is because to find the circumference you need Pie D(diameter)

so to get the surface area Mr.Backe wrote the answer down so here it is:

S.A.= 25²+5 pie 20+4(25)(5)

       = 625 + 314.2 + 500

       = 1439.2 cm²

 

 

 

 

 

Finding the suface area for the check your understanding.

So now we have the pool stairs and all the dimensions with.As it is shown in the picture below the side is sort of not a shape.We have a way to find the area of that.Cut the little edege off.Now we have 20 x 30, and for the rest of that object(the big piece) 40 x 60 because 30 is cut off from 90.We square it because there is two of these objects.Then we add the rest.80 x (40 + 60 + 20 + 30 +20).So the formula is:
2{20 x 30 + 60 x 40 } + 80 (40 + 60 + 20 + 30 + 20)
2(600) + (2400) +80 (170)
2(3000)+13600
6000+13600
19600 cm squared.



Now for the house that everyone has a hard time with. Before I start this you have to know that the bottom is something that you do not need fo this part. It isn't visable and pressed against something so we can't use it.Now for the triangles it is base x hieght divided by 2.Then we square it.Then we find the area for the rectangle and add the rest which is timesed by 10.
Here is how it is written:
2{4 x 6 divided by 2 + 5x6 } + 10(5+5+5+5)
2(12) + (30) + 10 (20)
2(42)+200
84+200
284 m squared
The next scriber is John.Good luck mister president.