HEYA
since perimeter of ΔABC=27.6cm
AB=9.6cm
BC=6cm
therefore AC= 12cm
[tex]27.6cm - 9.6cm - 6cm = 12cm[/tex]
since ΔABC~ΔBCD
therefore the sides will be proportional
let the perimeter of ΔBCD=x
[tex] \frac{9.6}{6} = \frac{27.6}{x} [/tex]
[tex]x = \frac{27.6 \times 6}{9.6} cm[/tex]
x=17.25cm
hope it helps you mate thanks for the question and if possible please mark it as brainliest
