A:B=2:3, B:C=4:5 এবং C:D=6:7 হলে, A:D নির্ণয় করি।
\(∵ A:B=2:3\)
বা, \(\cfrac{A}{B} = \cfrac{2}{3}\)
একইভাবে, \(\cfrac{B}{C}=\cfrac{4}{5}\)
এবং \(\cfrac{C}{D}=\cfrac{6}{7}\)
\(∴ \cfrac{A}{B}×\cfrac{B}{C}×\cfrac{C}{D} = \cfrac{2}{3}×\cfrac{4}{5}×\cfrac{6}{7}\)
বা, \(\cfrac{A}{D}=\cfrac{16}{35}\)
\(∴A:D=16:35\) (Answer)