Answer
0.368743
Work Step by Step
$Use$ $the$ $Change$ $of$ $Base$ $Formula$ $and$ $a$ $calculator$ $to$ $evaluate$ $the$ $logarithm$:
$\log_{12} 2.5$
Apply the Change of Base Formula: $\log_x y$ = $\frac{\log y}{\log x}$
$\log_{12} 2.5$ = $\frac{\log 2.5}{\log 12}$
Use a calculator and round to the sixth decimal place
$\approx$0.368743