Three solutions of Triblu indicator, all of equal concentration, were made at pH 1, pH 6 and pH 10.

The pH 1 solution had an absorbance at 620 nm of 0.318, while the pH 10 solution had an absorbance of 0.438.

If Triblu indicator has a pKa of 5.0, what would the absorbance of the pH 6 solution be at 620 nm?

Answer to three decimal places.