What is the common logarithm of 54.29?

2 Answers
Sep 10, 2015

log(54.29) ~~ 1.73472log(54.29)1.73472

Explanation:

x = log(54.29)x=log(54.29) is the solution of 10^x = 54.2910x=54.29

If you have a natural log (lnln) function but not a common loglog function on your calculator, you can find log(54.29)log(54.29) using the change of base formula:

log_a(b) = log_c(b)/log_c(a)loga(b)=logc(b)logc(a)

So:

log(54.29) = log_10(54.29) = log_e(54.29)/log_e(10) = ln(54.29)/ln(10)log(54.29)=log10(54.29)=loge(54.29)loge(10)=ln(54.29)ln(10)

Sep 10, 2015

If you are using tables, you need:

Explanation:

log54.29 = log(5.429 xx 10^1)log54.29=log(5.429×101)

  • log(5.429) +1.

From tables

log5.42 = 0.73400log5.42=0.73400

log5.43 = 0.73480log5.43=0.73480

5.4295.429 is 9/10910 of the way from 5.42 " to " 5.435.42 to 5.43, so we get
9/10 = x/80910=x80 so x=72x=72

by linear interpolation,

log(5.429) = 0.74372log(5.429)=0.74372

So
log(54.29) = 1.74372log(54.29)=1.74372

(I'm using == rather than ~~ in each case.)