1. **State the problem:** We need to find the value of $x$ where $x = \log_{10} 40$. 2. **Recall the definition of logarithm:** $\log_{10} 40$ means the power to which 10 must be raised to get 40. 3. **Use the change of base formula:** Since calculators often use natural logs or base 10 logs, we can write $$x = \log_{10} 40 = \frac{\ln 40}{\ln 10}$$ where $\ln$ is the natural logarithm. 4. **Calculate the values:** $$\ln 40 \approx 3.6889$$ $$\ln 10 \approx 2.3026$$ 5. **Divide to find $x$:** $$x = \frac{3.6889}{2.3026} \approx 1.6021$$ 6. **Interpretation:** This means $10^{1.6021} \approx 40$. **Final answer:** $$x \approx 1.6021$$