∆ABC ∼ ∆DEF such that AB = 9.1 cm and DE = 6.5 cm.
Question:

ABC ∼ ∆DEF such that AB = 9.1 cm and DE = 6.5 cm. If the perimeter of ∆DEF is 25 cm, what is the perimeter of ∆ABC?
(a) 35 cm
(b) 28 cm
(c) 42 cm
(d) 40 cm

Solution:

(a) 35 cm

∆ABC ∼ ∆DEF

$\therefore \frac{\text { Perimeter }(\triangle A B C)}{\text { Perimeter }(\triangle D E F)}=\frac{A B}{D E}$

$\Rightarrow \frac{\text { Perimeter }(\triangle A B C)}{25}=\frac{9.1}{6.5}$

$\Rightarrow$ P erimeter $(\triangle A B C)=\frac{9.1 \times 25}{6.5}=35 \mathrm{~cm}$