Question

$△$ ABC is such that AB = 3 cm, BC = 2 cm and CA = 2.5 cm.$△$ DEF is similar to $△$ABC. If EF = 4 cm, then the perimeter of $△$DEF is -

• A. 7.5 cm
• B. 15 cm
• C. 22.5 cm
• D. 30 cm

Answer 1

The correct option is B

15 cm

$\frac{AB}{DE}$ =$\frac{AC}{DF}$ = $\frac{BC}{EF}$ = $\frac{2}{4}$ = $\frac{1}{2}$

DE = 2 AB = 6 cm, DF = 2 AC = 5 cm.

$\therefore$ Perimeter of $△$DEF = (DE + EF + DF) = 15 cm.