The digits after the decimal point represent tenths, hundredths, and thousandths respectively.<br><br>
In 28.391:<br>
&bull; (a) The digit 9 is in the hundredths place, so its value is 9 hundredths = 0.09.<br>
&bull; (b) The digit in the tenths place (first decimal place) is 3.<br>
&bull; (c) The digit 1 is in the thousandths place, so its value is 1 thousandth = 0.001.<br><br>
Final Answer: (a) 0.09, (b) 3, (c) 0.001