To solve this problem we will apply the concept given by Pythagoras in the description of the lengths of the legs of a rectangular triangle and if equality against the square of the hypotenuse, that is

Here,
a, b = Legs of a triangle
c = Hypotenuse
According to the attached chart then we would have to

Substituting the given the lengths into the Pythagorean Theorem.

Therefore the distance x is 2830km.