816 Math (2009)

Monday, March 8, 2010

Tamika's surface area growing post

Rectangular prism

sorry i foregot to put the unit:
TSA= 10860cm2

Triangular prism

Cylinder

Karra's Surface Area Growing Post

Rectangular Prism

Top :

A=lxw

12x4.5

54x2

108cm2

Side:

A=lxw

4.5x 21

94.5x2

189cm2

Front:

A=lxw

12x21

252x2

504cm2

TSA=504+108+189 =
= 801 cm2

Cylinder

R=d/2
= 2.4x2
= 1.2

C=3.14xd
= 3.14x2.4
= 7.536

A= 3.14 x r x r
= 3.14 x 1.2 x 1.2
= 4.5216

TSA= 7.536+4.5216+75.36 =
= 87.4176 cm2

Triangular Prism

bxh/2
5x7/2
=17.5

bxh/2
5x7/2
=17.5

lxw
9x12
= 108

lxw
9x7
= 63

lxw
5x9
= 63

TSA = 63+63+108+17.5+17.5
=269 cm2

For triangular Prism I missed a number, so the number that is missing is 9!

Sunday, March 7, 2010

Jecelyn's Growing Post

Surface area of a rectangular prism

Surface area of a Cylinder

Area of a triangular prism

Sorry the pictures are kind of small and the video will be put up soon

Nadine's growing post

top:
lxw
12x4.5
54x2
=108

side:
lxw
10.4x4.5
46.8x2
=93.6

front
lxw
12x10.4
124.8x2
=249.6

TSA: 108+93.6+249.6= 451.2 cm 2

bxh/2
8x7/2
56/2
=28

bxh/2
8x7/2
56/2
=28

lxw
10.6x2.5
=26.5

lxw
2.5x7
=17.5

lxw
8x2.5
=20

TSA: 28+28+26.5+17.5+20 = 120 cm 2

r=d/2
r=9.5/2
r=4.75

2x3.14xrxr
2x3.14x4.75x4.75
=141.70

3.14xdxh
3.14x9.5x11
= 328.13

TSA: 141.70+ 328.13= 469.82 m 2

Surface area

In the past is about Surface area lxw in handing writing for the rectangular prism. For the Triangular prism lxw for the rectangles and bxh/2

for the triangles.

Let me show you how we did it.

if I did a rectangular prism so like, but first we do the formula.

l x w=A

#xside a=#

#xside a=#

then lxw= #

#x2=

#x2=

#x2= add them all up and you get the surface area Triangle l x w= b x h/2

By the time you got the answer add them up. Then you add the triangles and get the TSA ( TOTAL SURFACE AREA)

Oh.. one more Cylinder is a 3-dimensional circle

there is radius, circumference and diameter.