Use the form below to do your conversion.
Solution
Step1
Log21685=Log(685) ÷ Log(21)
Log(685)= 2.8356905714924
Log(21)=1.3222192947339
Log21685=2.8356905714924 ÷ 1.3222192947339
Ans=2.144644676406
Step2
Alternatively, the logarithm can be calculated like this.