\[\boxed{\text{6.268.}}\]
\[\textbf{а)}\ 1,225 \cdot 30 = 36,75\ (кг)\text{\ .\ }\]
\[\textbf{б)}\ 1,225 \cdot 0,1 = 0,1225\ (кг)\text{.\ }\]
\[\textbf{в)}\ 1,225 \cdot 7,8 = 9,555\ (кг)\text{.\ }\]
\[\textbf{г)}\ 1,225 \cdot 0,7 = 0,8575\ (кг)\text{.\ }\]