[ \textAbsorbance = m \times \textConc + c ]

[ 0.415 = 0.831 \times \textConc + 0.001 ] [ \textConc = \frac0.415 - 0.0010.831 = 0.498 \text mg/mL ]

If the unknown was diluted (e.g., 10×), multiply by the dilution factor:

For unknown absorbance = 0.415: