\[\boxed{\text{6.315.}}\]
\[\textbf{а)}\ 0,6\ :0,5 = 6\ :5 = 1,2\ \]
\[\textbf{б)}\ 9,28\ :2,9 = 92,8\ :29 = 3,2\ \]
\[\textbf{в)}\ 19,035\ :0,81 = 1903,5\ :81 =\]
\[= 23,5\ \]