This is how you do it.
You might want a calculator for some so here's an online one.
After that, Check this
As you can see, 360° is a circle (which is considered a polygon with infinite sides).
So to get the number, divide the sides of the polygon by the degrees of a circle.
The only problem is that it might glitch with decimals.
So basically, it is a "Leave a trail" block.
Inside it, you put "Move forward (___)" and add a "Turn (360 ÷ (number of sides))"
Pls comment if it worked for you.