It’s 5 since you’d use Pythagorean theorem
I think you would put 570 in the blank since 19 x 3 = 57
Take the expression x^2/3 which has an exponent of 2/3. The top of the fraction refers to the power - that is x^2 ( x squared). and the 3 indicates a cubic root.
So in radical form it is ∛(x^2)
Converting radical to exponent an example would be
∛(x^5) = x^(5/3)