A prism is a solid object having two identical bases, hence the same cross section along the length. Prism are called after the name of their base. A rectangular prism is a solid whose base is a rectangle. Multiplying the three dimensions of a rectangular prism: length, width and height, gives us the volume of a prism:

$V=L\times W\times H$

FOR THE ORIGINAL PRISM WE HAVE THE FOLLOWING DIMENSIONS:

$L=14cm \\ \\ W=6cm \\ \\ H=3cm$

In fact, the volume is $252cm^3$ because:

$V=14\times 6\times 3 \therefore V=252cm^3$

Now the height of the prism was changed from 3 centimeters to 6 centimeters to create a new rectangular prism, therefore:

FOR THE NEW PRISM WE HAVE THE FOLLOWING DIMENSIONS:

$L=14cm \\ \\ W=6cm \\ \\ H=6cm$

So the new volume is:

$V=14\times 6\times 6 \therefore V=504cm^3$

<h3><em>What do we know about the volume of the new prism?</em></h3>

<em>Well, the volume has increased from </em> $252cm^3 \ to \ 504cm^3$ <em>and since</em> $504=2\times 252$ <em>we can say that the new volume is two times the original volume.</em>