## Thursday, April 17, 2008

### Josephine's scribe post

- Circumference of a circle

- Area of a circle

- Surface area of a cylinder

- Volume of a cylinder

Formulas:

Circumference of a circle - pi d (pi *d) OR pi 2 r (pi * 2 * r)

Area of a circle - pi r² (pi * r²)

Surface area of a cylinder -

area of circle = (pi * r²) * 2

+

area of square = H * C

=

surface area of a cylinder

Circumference = pi r 2 (pi * 2 * r) (also needed to find surface area of a cylinder)

Volume of a cylinder - area of the base * height

Voicethread of Yellow Paper:

coming soon...:)

## Tuesday, April 15, 2008

### Rectangular Prism Test Scribe Q.1

**find the surface area and volume of...**

**VOL= area of base x height**

**BASE: lxw=**

**4x4=**

**16**

**HEIGHT= 4**

**SA= 2(hxl)+2(wxh)+2(lxw)=**

**SA= 2(16)+2(16)+2(16)=**

**SA= 32+32+32=**

**SA=96cm2**

## Monday, April 14, 2008

### Karen's B.O.B

For Finding the Surface Area you just follow the fomula! 2(HxL) + 2(HxW) + 2(LxW)

Fomula:

Net of a Rectangular Prism:

Once you know the formula you can start filling in what you know.

Finding the Volume of a Rectangular is too. You just have to follow the fomula.

Formula:

Now we can answer the fomula! By filling in the information we know!

### Israelie's BOB

### Kathleens B.O.B

Surface area of a rectangle prism:

A way to solve this problem:

L= 12

W= 4

H=12

Formula:

surface area(sa) = 2(hxl) + 2(hxw) + 2(lxw)

sa= 2(12x12) + 2(12x4) + 2(12x4)

sa= 2(144) + 2(48) + 2(48)

sa= 288 + 96 + 96

sa= 480 cm sqaured

-----------------------------------------------------------------------------------------------

Volume of a rectangular prism:

Formula:

### Erick's BOB

Now the Area of a rectangular Prism is the area of all of the sides of the shape added up.

This is the net. This gives you a very good visual aid in helping you find the surface area of the shape because it shows all of the sides and squares.

Also it just looks neater.

Ok. so, shown on this net we have each side measuring 5cm. Now i did some work that is not shown here, but all i did was get the area of the box by using the formula, LxW. So 5x5 would give me the area of one square.

Now all we need to do is use a simple formula to find the surface Area.

Here's the formula for that!

Surface Area= 2(hxl)+2(hxw)+2(lxw)

Surface Area=2(5x5)+2(5x5)+2(5x5)

Surface Area=2(25)+2(25)+2(25)

Surface Area= 50 + 50 + 50

Surface Area = 150cm2

Now Volume is really simple! All you have to do is Get the measurements of all three sides and multiply them using this formula.

Volume of a Rectangular Prism

LxWxH

5cm2x5cm2x5cm2=125cm3

Please note the cubed!

Another way is Area of base X Height

(25cm2)5cm2=125cm2

### Josephine's B.O.B

L=6cm

W=2cm

H=2cm

SA = 2(H * L) + 2(H * W) + 2(L * W)

= 2(2 * 6) + 2(2 * 2) + 2(6 * 2)

= 2 * 12 + 2 * 4 + 2 * 12

= 24 + 8 + 24

= 56cm²

click for bigger picture

Volume of a rectangular prism:

L=4cm

W=2cm

H=2cm

V = (L* W) * H

= (4 * 2) * 2

= 8 * 2 = 16cm³

OR

= (area of the base) * H

= 8 * 2

= 16cm³

click for bigger picture

### Exequelle's BOB

**Surface Area of A Rectangular Prism**

2(W*H)+ 2(H*L) + 2(L*W)= The surface Area.

H = 1cm2

2(8cm2) + 2(4cm2) + 2 (32cm2) =

**Volume of a Rectangular Prism**

(W x L) x H = Volume

Base = 32 Height = 1 32 x 1 = 32cm3

### Jordan's BOB

Surface area is all of the areas on all of the sides added up on a solid figure such as ( in our case) a rectangular prism.

This is called a net. ---------------------> Nets are made out of shapes like this cube.

This is how you would change a cube into a net:

Heres how to get the surface area of a rectangular prism:

We know that there are two 6cm squared, two 2cm squared and two 3cm squared.

This is what it looks like: ( don't forget the formula)

2(6cm squared) + 2 (6cm squared) + 2 (3cm squared) Now do some math

36cm squared + 4cm squared + 9cm squared =

49cm squared.

A longer way to do it is like this:

(6x6) + (2x2) + (3x3)

36 + 4 + 9 =

49cm squared.

Volume Of A Rectangular Prism

Lets say that we are trying to find the volume of a rectangular prism.

L = 6

W = 2

H =2

Here's how you solve it.

L x W x H = (6cm squared x 2cm squared) x 2 cm squared =

24 cm squared.

Multiple methods to show this are

Length x width x height ( height also known as depth)

or you could use

Area of base x height

### B.O.B

### Charmaines B.O.B

**In my B.O.B we are going to find out the**

*volume*and the*surface area*of this**rectangular prism.**

Surface Area

**Here is my formula for my rectangular**

**prism.**

**2 ( 4 x 2 )+ 2 ( 1 x 2 )+ 2 ( 4 x 1 ) =**

2 (8 cm2 ) +2 ( 2 cm2 ) + 2 ( 4cm2 ) =

2 (8 cm2 ) +2 ( 2 cm2 ) + 2 ( 4cm2 ) =

**16 cm2 + 4cm2 + 8cm2 = 28 cm2**

**The second way in finding the surface**

**area.**

**2cm 2 + 2cm2 + 4 cm2 + 4 cm2 + 8cm2**

**+ 8 cm 2 = 28 cm2**

**Now here is the volume for my rectangular**

**prism.**

**( L x W ) x H = area or you can also use.......**

**Area of the base x height**

**Formula :**

**( L x W ) x**

**H = area**

L = 8

L = 8

**W = 4**

**( L x W ) x H H = 1**

**( 8 x 4 ) x 1 =32 x 1 = 32 cm3**

**Or the other way is**

**Area of the base x height = area of a rectangular**

**prism. The area of our base is 32 and 32 x our**

### Kevin's BOB

*In this B.O.B. we are going to find out how*

*to find the volume and the surface area of*

*a rectangular prism.*

What we did was draw a net of our shape out on gird paper and each cube represents 1 cm and then we labled it. Make sure the formula is writen down. The formula is ....

**2 ( 4 x 2 )+ 2 ( 1 x 2 )+ 2 ( 4 x 1 ) =**

**2 (8 cm2 ) +2 ( 2 cm2 ) + 2 ( 4cm2 ) = ****16 cm2 + 4cm2 + 8cm2 = 28 cm2**

A secccond way is to just add the lengths together like this... *2cm 2 + 2cm2 + 4 cm2 + 4 cm2 + 8cm2 + 8 cm 2 = 28 cm2*

To find the area of a rectangular prism you can use 2 diffrent stratigies or formulas. You can use...

( L x W ) x H = area or you can also use....... *Area of the base x height. in this B.O.B we are going to solve it using both. First we drew a net of the rectangular prism.*

*Fromula :* ( L x W ) x H = area

L = 8

W = 4 ( L x W ) x H

H = 1 ( 8 x 4 ) x 1 =

32 x 1 = 32 cm 3

*The seccond way to solve this equation is to use the formula >>>>>>* Area of the base x height = area of a rectangular prism.

*The area of our base is 32 and 32 x our height would be 32 x 1= 32 cm 3. Since we are dealing with a 3 dimensional shape we have to make sure we use cubed witch is 3 instead of 2. *

### Judy's BOB

1.what is surface area?

surface area is the total area of the outside of a 3-D shape

2. how do you find the surface area?

first take your shape, and draw what it

would look like if it were opened and laid out:

Then measure the sides,

and find the area of each separate square (or rectangle)

.... suppose the sides are all 2cm long.

The formula to find the area of a square is

Length x Width so the area of each square would be 4cm²

Finally, use the formula to find the surface area.

you can either use:

(area = a)

a+a+a+a+a+a= surface area

4cm²+4cm²+4cm²+4cm²+4cm²+4cm²= 24cm²

OR

**2 (HxL)+ 2(HxW)+ 2(LxW)**

2(2x2)+ 2(2x2)+ 2(2x2)

2(4)+2(4)+2(4)=

8cm+8cm+8cm= 24cm²

------------------------------------------------------------------------------------------------

THE VOLUME OF A RECTANGULAR PRISM

1. what is volume?

the amount of space an object takes up. in this case, a rectangular prism

2. How do you find the volume?

take a rectangular prism, and measure

it's length, width, and depth (also called height)

Then use the formula to find out the volume. You can use:

length x width x depth

3cm x 5cm x 2 cm

=30cm³

OR

Area of base x depth

(3cm x 5cm) x 2cm

15cm² x 2cm= 30cm³