Class 9th math 2.4 solution english PCTB

Question 5: Find the values of the following with the help of logarithm table:

\((iii)\) \(\quad\) \(\large{\frac{( 20.46)^{2} \times ( 2.4122)}{754.3} }\)

Solution:

Let

\[x=\frac{( 20.46)^{2} \times ( 2.4122)}{754.3}\]

Taking logarithm on both sides, we get

\[\log x=\log\left(\frac{( 20.46)^{2} \times ( 2.4122)}{754.3}\right)\]

\[
\begin{align*}
&=\small{\log( 20.46)^{2} +\log 2.4122-\log 754.3}\\
&=\small{2\log 20.46+\log 2.4122-\log 754.3}\\
&=2( 1.3109) +0.3824-2.8775\\
&=0.1267\\
\end{align*}
\]

Taking antilog on both sides, we get

\[
\begin{align*}
\text{anti-log}(\log x) &=\text{anti-log}( 0.1267)\\
x&=1.339\\
\end{align*}
\]

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