平方根について

2 = (5/4)(5/4)(32/25)
　= 1.25・1.25・1.28
　= {(1.25+1.25+1.28)/3}^3
　= 1.26^3
2^{1/3} = 1.26

2 = (7/5)(10/7)
　= {(7/5 + 10/7)/2}^2
　= (99/70)^2,
√2 = 99/70 = 1.4142857