# How do you use the Change of Base Formula and a calculator to evaluate the logarithm log_8 77?

Jun 12, 2018

${\log}_{8} 77 \approx 2.08893$

#### Explanation:

${\log}_{a} b = \ln \frac{b}{\ln} a$

$\therefore {\log}_{8} 77 = \ln \frac{77}{\ln} 8$

$\approx \frac{4.34381}{2.079442}$

$\approx 2.08893$

Check: ${8}^{2.08893} \approx 77.00$