Banach-Mazur distance between $P_5$ and $P_3$ is $d(P_5,P_3)=1+\frac{\sqrt5}2$ where $P_n$ is regular polygon in $n$ sides. Do closed form or approximate results exist for
$d(P_n,P_k)$?
$d(P_n^{\otimes t},P_k^{\otimes t})$ where $\otimes t$ is tensor product?
$d(P_n^{\times t},P_k^{\times t})$ where $\times t$ is cartesian product?
distances between Minkowski sums of polygons?
distances between Unions of polygons (with right modification of distance)?
At least do we know a situation with regular polygons where the distance becomes transcendental?