Solution
= Solution
For the <sphere>, $\chi=2$, and the same incidence identity gives
$$
2=V-\frac E3,
\qquad E=3(V-2).
$$
Therefore
$$
\boxed{\overline d=\frac{2E}{V}=6-\frac{12}{V}<6}.
$$
= Solution
For the <sphere>, $\chi=2$, and the same incidence identity gives
$$
2=V-\frac E3,
\qquad E=3(V-2).
$$
Therefore
$$
\boxed{\overline d=\frac{2E}{V}=6-\frac{12}{V}<6}.
$$