No, they aren't
12² + 12²=16²
288=256
so they aren't a pythagorean triple
I'm pretty sure you are asking for the value of b. Let's actually write it and then solve it:

Solving for b yields:

So,
b = 19.59. If you want the answer in simplified radical form, we can also do that:

So,
b = 8√6 = 19.59
Answer: You would need 512 cubic centimetres
Step-by-step explanation: The first approach to this question would be to understand the properties of the shape given in the question.
If a cube has an edge with length 8 cm, then all edges measure 8 cm as well. That is one property of a cube. Hence, the length, width and height all measure 8 cm each.
The volume of a cube is given as follows;
V = L x W x H (and the answer is expressed as V³)
Since the length , width and height all measure 8 cm, the volume can simply be expressed as
V = L x L x L
V = L³
V = 8³
V = 512 cm³
Therefore to completely fill a cube with edge length of 8 cm you would need 512 cubic centimetres.