Others have summarised lemmy, lemmy.world and its use quite well already, so i just looked for the connection to perchance:
I checked perchance.org and they mention that they have a community on lemmy where one can ask for help or share creations. (Similar to the “No Stupid Questions” community you posted this to)
They specifically link to this community: !perchance@lemmy.world (https://lemmy.world/c/perchance)
So no real relationship other than that they use Lemmy as a platform for their users to exchange on and use lemmy.world as a “provider” for their community space (or “forum” in older words)


Surprised it wasn’t recommended yet: Rowenta