Ko vẽ được hình :(
b/ \(\frac{h}{h'}=\frac{d}{d'}\)
\(\frac{h}{h'}=\frac{f}{f-d'}\)
\(\Rightarrow\frac{d}{d'}=\frac{f}{f-d'}\Leftrightarrow\frac{6}{d'}=\frac{10}{10-d'}\Leftrightarrow d'=3,75\left(cm\right)\)
\(h'=\frac{0,05.3,75}{6}=\frac{1}{32}\left(cm\right)\)