need advice for this skill chart table please

Hello ,

1. I want to make a skill chart file for my student(see attachment).
2. Basically 1st sheet is the mark of the subject
3. 2nd sheet is the skill chart pie for the subject referring to 1st sheet
   the 1st and 2nd sheet is related, meaning when I change the marks at the 1st sheet, the skill chart pie at the 2nd sheet will change automatically..
   
   Then, student with low mark will automatically shows in a table student need more improvement.
   
   QUESTION:
   1.Is it possible if I enter the mark e.g. 4 equal 100% at the 1st sheet, automatic a full chart pie appear at the second sheet. How should I do it?
   I don't know how to relate from one sheet to another sheet.
   
   2.and, I want to monitor for weak student who failed (score 25% or 2). When the student score 2 , automatically his/her name appear in the table students need improvement..
   Can you enlighten me about this thing..
   Thank you