Poiseuille's law states that the resistance $R$ for blood flowing in a blood vessel varies directly as the length $L$ of the vessel and inversely as the fourth power of its radius $r$. Stated as an equation,
$$
R(L, r)=k \frac{L}{r^{4}} \quad k \text { a constant }
$$
Find $R_{L}(4,0.2)$ and $R_{r}(4,0.2),$ and interpret the results.