Many lengths, only one radius

The area of a regular polygon can be written as $\frac{n.l.r}{2}$ , where $n$ is the number of sides, $l$ is the length of each side and $r$ is the length of the radius of the inscribed circumference $\Gamma$ . As we know, if the area of $\Gamma$ is $1369\pi$ , its radius is equal to $37$ . From the equation, we get:

$A=2.37^{3}.3^{2}=\frac{74.l.37}{2}\rightarrow \boxed {l=666}$