Okay, please do I'm eager to learn how that x becomes cm, and how does cm correlates various sizes of applications. I just want to know how is that 1 cm applied in websites as well as billboards at the same time with 1 cm clear space. Please enlighten me.

http://brand.opera.com/brandbook/identity-guidelines
https://billysweeney.com/squarespace-branding/
https://www.apple.com/legal/sales-support/certification/docs/logo_guidelines.pdf