Answer
(a) 1.430677
(b) 3.680144
(c) 1.651496
Work Step by Step
Since, change of base formula defines $\log_{a}x=\frac{logx}{loga}$
Therefore,
(a) $\log_{5}10=\frac{log10}{log5}$
Hence, $\log_{5}10=\frac{log10}{log5}=1.430677$
(b) $\log_{3}57=\frac{log57}{log3}$
Hence, $\log_{3}57=\frac{log57}{log3}=3.680144$
(c) $\log_{2}\pi=\frac{log\pi}{log2}$
Hence, $\log_{2}\pi=\frac{log\pi}{log2}$ =1.651496
