Covid19 has spread globally. When the Covid-19 pandemic occurs, schools must be closed or partially opened, which affects teaching and learning. Educational innovations to deal with epidemics such as Covid-19 and other urgent epidemics are very important. Therefore, the three cores of Education 4.0 knowledge applicable to pandemics such as COVID-19 are simple, self-learning and technology-integrated knowledge (SST knowledge). Simple knowledge is the most important core of Education 4.0 , it same as Albert Einstein quotes: everything should be made as simple as possible, but not simpler, If you can't explain it simply you don't understand it well enough, We cannot solve our problems with the same thinking we used when we created them. Peter Chew Method for Solution of Triangle is a simple method to solve the same problem, compare current methods. Use Peter Chew method and Peter Chew rule in Peter Chew Triangle Diagram to make the diagram guide students to solve any problem of the topic solution of the triangle is simple with just one rule. Programming Peter Chew Triangle Diagram as Peter Chew's Triangle Diagram Calculator makes it easier for the calculator to guide and solve any problem with just one rule, which will strengthen technology-integrated education, making teaching and learning more effective and fun. Peter Chew Triangle Diagram and Application(preprint) is share at World Health Organization(WHO, ID: ppcovidwho-308372).because objective Peter Chew Triangle Diagram is to help the teaching of mathematics, especially when similar covid-19 problems arise in the future. Author i) Program Chairs for The 11th International Conference on Engineering Mathematics and Physics held in Saint-Etienne, France on July 7-9, 2022 . http://www.icemp.org/committee.html ii)Keynote Speaker [AI age Calculator, PCET Calculator] of the 8th International Conference on Computer Engineering and Mathematical sciences (ICCEMS 2019). https://www.iccems.com/2019/WB/v1/index.html@id=0.html. iii) Keynote Speaker [AI age Calculator, PCET Calculator] of the International Conference on Applications of Physics , Chemistry & Engineering Sciences, ICPCE 2020. , in University Malaya, Malaysia. https://www.facebook.com/imrf.in/photos/a.354300178063577/1433507146809536/?type=3&theater iv) Invited speaker [AI age Calculator, PCET Calculator] of the 24th Asian Mathematics Technology Conference (ATCM 2019), Leshan, China.