Answer:
~8.66cm
Step-by-step explanation:
The length of a diagonal of a rectangular of sides a and b is

in a cube, we can start by computing the diagonal of a rectangular side/wall containing A and then the diagonal of the rectangle formed by that diagonal and the edge leading to A. If the cube has sides a, b and c, we infer that the length is:

Using this reasoning, we can prove that in a n-dimensional space, the length of the longest diagonal of a hypercube of edge lengths
is

So the solution here is

It's the letter D hope it helps
Two multiply 2 monomials, you have to multiply the coefficients and add the degrees. For example
2x^2 × 3x^3 =
6x^5