Question

Use common logarithms or natural logarithms and a calculator to evaluate to four decimal places.
log4 20

Answer 1

\[\Large \log_a(x) = {\log_b(x) \over \log_b(a) }\]

Answer 2

so,
\[\large\log_4(20) = {\log 20 \over \log 4}\]OR\[\large\log_4(20) = {\ln 20 \over \ln 4}\]