Let a curve \( y=y(x) \) pass through the point \( (3,3) \) and the area of the region under this curve, above the \( x \)-axis and between the abscissae \( 3 \) and \( x(>3) \) be \( \left(\dfrac{y}{x}\right)^{3} \). If this curve also passes through the point \( (\alpha,6\sqrt{10}) \) in the first quadrant, then \( \alpha \) is equal to ______.
