To calculate the approximate percent increase from $800,000 to $900,000, you can use the following formula:
\[ \text{Percent Increase} = \frac{\text{New Value} - \text{Old Value}}{\text{Old Value}} \times 100 \]
Substituting the values:
\[ \text{Percent Increase} = \frac{900,000 - 800,000}{800,000} \times 100 \]
\[ \text{Percent Increase} = \frac{100,000}{800,000} \times 100 \]
\[ \text{Percent Increase} = 0.125 \times 100 \]
\[ \text{Percent Increase} = 12.5% \]
Therefore, the approximate percent increase is about 13%.
So, the correct answer is: The approximate percent increase is 13%.