Use the form below to do your conversion.
Solution
Step1
Log213991=Log(3991) ÷ Log(21)
Log(3991)= 3.601081727784
Log(21)=1.3222192947339
Log213991=3.601081727784 ÷ 1.3222192947339
Ans=2.7235132191205
Step2
Alternatively, the logarithm can be calculated like this.