Using Log and Antilog in Calculations - SS2 Mathematics Lesson Note
Example 3 Evaluate the following logarithm:
-
\(348.3 \times 5.427\)
\(456.2 \div 98.76\)
\(\frac{{(361.2)}^{3} \times 75.09}{{(11.32)}^{2} \times \sqrt{92.5}}\)
Solution
-
\(348.3 \times 5.427\)
| NUMBER | LOGARITHM |
|---|---|
| \[348.3\] | \[2.5420\] |
| \[5.427\] | \[0.7346\] |
| \[348.3 \times 5.427\] | \[2.5420 + 0.7346 = 3.2766\] |
\[antilog\ 3.2766 = 1891\]
-
\(456.2 \div 98.76\)
| NUMBER | LOGARITHM |
|---|---|
| \[456.2\] | \[2.6592\] |
| \[98.76\] | \[1.9946\] |
| \[348.3 \times 5.427\] | \[2.6592 - 1.9946 = 0.6646\] |
\[antilog\ 0.6646 = 4.619\]
-
\(\frac{{(361.2)}^{3} \times 75.09}{{(11.32)}^{2} \times \sqrt{92.5}}\)
| NUMBER | LOGARITHM | |||
|---|---|---|---|---|
| \[{(361.2)}^{3}\] | \[3 \times 2.5577\] | \[7.6731\] | ||
| \[75.09\] | \[1.8756\] | |||
| \[7.6731 + 1.8756 = 9.5487\] | ||||
| \[{(11.32)}^{2}\] | \[2 \times 1.0539\] | \[2.1078\] | ||
| \[\sqrt{92.5}\] | \[1.9661 \div 2\] | \[0.9831\] | ||
| \[2.1078 + 0.9831 = 3.0909\] | ||||
| \[9.5487 - 3.0909 = 6.4578\] |
\[antilog\ 6.4578 = 2,869,000\]