Understanding Fedora, Redhat and CentOS

Talking about Linux Distribution these three are quite famous for maintaining the server and security perspectives. I don't mean to say there are only these three distributions for servers and network security, I would absolutely be wrong. In that case Slackware, Arch, Black Arch, Kali, Bodhi are some name which shouldn't be missed. I agree there are even more. But being interrelated with each other, people generally get confused about following three Linux Distributions: 

  • Fedora
  • Redhat
  • CentOS
They get confused regarding following points:
  •  Do they belong to same company?
  • As Redhat is available as a commercial version do other distributions cost money as well?
  • Who maintains them?
  • How  often their stable versions are released?

I was also little unclear previously, so I did a little study about these three distribution and went through wikipedia. Being convinced myself I draw this diagram listing their features in order top to button.

I wish this will  somehow help.