Original formula > = (A 2+B 2+C 2)/(A+B+C)

According to:

Available: a 2+b 2+c 2 > = (a+b+c) 2/3

So: original type >; =(a^2+b^2+c^2)/(a+b+c)>； =(a+b+c)/3

High school math and physical education teachers can only earn one third ... hehe.