Answer:
Approximately 17.88x or 
Step-by-step explanation:
Use pythagorean formula. In a rhombus the diagonals bisect each other and they are perpendicular, so you could have a right triangle with legs of 2x and 4x, the hypoteneuse would then be 
which is approximately 4.47x. In a rhombus all 4 sides are the same, so multiply that by 4 and you get the perimeter. 4(4.47x) = 17.88x or if you simplify the radical instead it's
Given equation is
It can be written as follows.
Which is of the form
where a=3 and b=4.
We know that the coordinates of the vertices are (a,0) and (-a,0)
Substitute a=3, we get
The vertices are (3,0) and (-3,0).
We know that the coordinates of the foci are (c,0) and (-c,0)
![c=\sqrt[]{a^2+b^2}](https://tex.z-dn.net/?f=c%3D%5Csqrt%5B%5D%7Ba%5E2%2Bb%5E2%7D)
Substitute a=3 and b=4, we get
![c=\sqrt[]{3^2+4^2}=\sqrt[]{9+16}=\sqrt[]{25}=5](https://tex.z-dn.net/?f=c%3D%5Csqrt%5B%5D%7B3%5E2%2B4%5E2%7D%3D%5Csqrt%5B%5D%7B9%2B16%7D%3D%5Csqrt%5B%5D%7B25%7D%3D5)
Substitute c=5, we get
Hence the foci are (5,0) and (-5,0).
A scaled triangle because they are all different lengths
216inches cubed is the answer
