A rectangular prism has a length of 12 in., a width of 5 in., and a height of 414 in.

The prism is filled with cubes that have edge lengths of 14 in.

How many cubes are needed to fill the rectangular prism?

Respuesta :

Answer:

16320 cubes are needed to fill the rectangular prism.

Step-by-step explanation:

Given : A rectangular prism has a length of 12 in., a width of 5 in., and a height of [tex]4\frac{1}{4}[/tex] in.

The prism is filled with cubes that have edge lengths of [tex]\frac{1}{4}[/tex] in.

To find :  How many cubes are needed to fill the rectangular prism?

Solution :

A rectangular prism has

Length of 12 in.

Width of 5 in.

Height of [tex]4\frac{1}{4}=\frac{17}{4}[/tex] in.

Volume of rectangular prism is [tex]V=L\times B\times H[/tex]

[tex]V=12\times 5\times \frac{17}{4}[/tex]

[tex]V=255 in^3[/tex]

A cube has length of [tex]\frac{1}{4}[/tex] in.  

Volume of cube is [tex]V=L^3[/tex]

[tex]V=\frac{1}{4}^3[/tex]

[tex]V=\frac{1}{64}in^3[/tex]

Cubes are needed to fill the rectangular prism is

[tex]=\frac{\text{Volume of rectangular prism}}{\text{Volume of cubes}}[/tex]

[tex]=\frac{255}{\frac{1}{64}}[/tex]

[tex]=255\times 64[/tex]

[tex]=16320[/tex]

Therefore, 16320 cubes are needed to fill the rectangular prism.

Answer:

There are needed 9 cubes.

Step-by-step explanation:

The volume of a rectangular prism is

[tex]V=l \times h \times w[/tex]

Where [tex]l[/tex] is the length, [tex]h[/tex] is the height and [tex]w[/tex] is the width.

In this case, we have

[tex]l=12in\\h=414in\\w=5in[/tex]

Replacing this values we can find the volume

[tex]V=12in (5in)(414in)=24,840 in^{3}[/tex]

Now, the cubes needed have edge lengths of 14 in, that means their volume is

[tex]V_{cube} = l^{3} =(14in)^{3}=2,744 in^{3}[/tex]

To know how many cubes are needed, we just need to divide

[tex]n=\frac{24,840}{2,744} \approx 9[/tex]

Therefore, there are needed 9 cubes.