If 0.75 : x :: 5 : 8, then x is equal to:

This is a proportion problem. In proportions, the product of the means (middle terms) is equal to the product of the extremes (outer terms).

So, we can set up the equation like this:

0.75/x = 5/8

To solve for x, we can cross-multiply:

0.75 * 8 = 5 * x

6 = 5x

Then, divide both sides by 5 to solve for x:

x = 6/5

So, x = 1.2