## Tuesday, April 15, 2008

### jordan's bob

On this bob I'll be explaining how to get the surface area and volume of a cube and a rectangular prism and I'll also show you the net.
this is a cube:
L = length
H= Height
W= Width

this the net of a cube

how to find the surface area and volume of a cube.
To get the surface area of a cube first you have to find all the area of the squares in the net.
the cube has a equal sides, if all sides was 3 cm you just have to find the area of one box and all the box are the same.
like this:
you just have to add all the area.
9cm2 + 9cm2 + 9cm2 + 9cm2 + 9cm2 + 9cm2 = 54cm2
or
SA= 6 (9cm2)
= 54cm2

or
S.A=2(l x W) + 2(h x l) + 2(h x w)

Volume
Formula:
V=L x W x H
V=(3cm x 3cm )x 3cm
V=9cm x 3cm
V=27 cubic cm
Rectangular prism.

This is the net of rectangular prism looks like:
to get the surface area of rectangular prism you need to use the formula:
SA= 2 (l x w) + 2 (h x w) 2 + (h x l).

L = 5cm, W = 2cm, H = 6cm

SA= 2 (l x w) + 2 (h x w) + 2 (h x l)
SA= 2 (5cm x 2cm) + 2 (6cm x 2cm) + 2 (6cm x 5cm)
SA= 2 (25cm squared) + 2 (36cm squared) + 2 (30cm squared)
SA=625cm squared + 1296cm squared + 900cm squared
SA=2821cm squared

Volume formula:
V=(L x w)H
V=(5cm x 2cm)6cm
V=25cm x 6cm
V=150 cubic cm