Gauss–Wantzel theorem states that A regular n-gon is constructible with straightedge and compass if and only if $n = 2^kp_1p_2...p_t$, where $p_i$'s are distinct Fermat primes (A Fermat prime is a prime number of the form $2^{m}+1$). A Poncelet polygon (or bicentric polygon) is a polygon which is...

Gauss–Wantzel theorem states that A regular n-gon is constructible with straightedge and compass if and only if $n = 2^kp_1p_2...p_t$, where $p_i$'s are distinct Fermat primes (A Fermat prime is a prime number of the form $2^{m}+1$). A Poncelet polygon (or bicentric polygon) is a polygon which is...