Monday, February 7, 2011

Emily's Circle Surface Area Scribe Post

Notes:

-bases are circles
-diameter cuts a circle in half
-radius
is half the diameter
-circumference is the perimeter of a circle
-pi is the ratio between circumference/diameter or 3.14
-circumference, pi.d=c
-radius, d/2=r
-diameter, r.2=d or c/pi=d
-area of a square, pi.r squared or pi.r.r
-make a square with the radius and multiply by pi

EX.





Here are some questions we did in class:





Here is a LINK I found on area.



Here is a video:







What is the radius of a circle with a diameter of 8cm?






Create your own poll at Flisti.com


Cylinder Volume and Volume Problems

Volume Problem


d/2=r
8/2=r
4m=r

pi.r.r.h
(3.14x4x4)x10
(50.24m^2)10m
502.4m^3



Since it is a semi circular trough the area has to be divided by two.
502.4cm^3/2=251.2m^3

The volume of the semi circle is 251.2m^3


Volume Problem


To convert a meter to a centimeter you multiply it by 100.


0.25mx100=25cm

d=25cm

d/2=r

25/2=r

12.5cm=r

1mx100=100cm

height of cylinder= 100cm

0.35mx100=35cm

height of triangle=35cm

0.4mx100=40cm

base of triangle=40cm

1.4mx100=140cm

height of the triangular prism=140cm



pi.r.r.h

(3.14x12.5cmx12.5cm)x100cm

(490.625cm^2)x100cm

v=49062.5cm^3

bxh/2.h

(40cmx35cm/2)x140cm

(700cm^2)x140cm

v=98000cm^3

98000cm^3-49062.5cm^3=48937.5cm^3

48937.5cm^3 is needed to make the clay planter.



Here is the volume video I created:

3 comments:

  1. Sorry, my blog was not letting me fix my pictures so I deleted my old post and did it over again.

    ReplyDelete
  2. Nice job Emily! I like the video and link that you put. I think next time you should make the writing in your picture a little bit larger.

    ReplyDelete
  3. Great job Emily! i really like how you included your information on your pictures! maybe next time you should make the picture more visable. Other then that your post is very nice.

    ReplyDelete