(0.785) (d squared) = 5024 solve for x?

This equation involves no x variable, so I assume you want to solve this for D.

First of all, you can divide both sides by 0.785 to get

Since the right hand side is positive, the equation make sense (otherwise we would be asking a square, i.e. a positive number, to equal a negative number). So, we can extract the square root from both sides:

the answer is 0.071

good luck! : d