on which PR is based on?

[JamesRichard]

Page Rank is the degree algorithmic rule employed by the Google to rank websites in their computer search results. To roughly estimate the number and quality of links to a page and to determine how important the website is Google use page rank.

[rtcwebdeveloper]

Pagerank is what google uses to determine the importance of a web page. It's one of many factors used to determine which pages appear in search results. Pagerank is measured on a scale of one to ten and assigned to individual pages within a website, not the entire website.