When blood flows along a blood vessel, the flux [math] (the volume of blood per unit time that flows past a given point) is proportional to the fourth power of the radius [math] of the blood vessel: [math] (Poiseuille's Law).

A partially clogged artery can be expanded by an operation called angioplasty, in which a balloon-tipped catheter is inflated inside the artery in order to widen it and restore the normal blood flow.

It can be shown (do it) that the relative change in [math] is about four times the relative change in [math]. So, how will a [math]% increase in the radius affect the flow of blood?

percent increase in blood flow.