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Home » In ∆ABC, it is given that AB = 9cm, BC = 6cm and CA = 7.5cm. Also, ∆DEF is given such that EF = 8cm and ∆DEF~∆ABC. Then, perimeter of ∆DEF is (a) 22.5cm (b) 25cm (c) 27cm (d) 30cm
In ∆ABC, it is given that AB = 9cm, BC = 6cm and CA = 7.5cm. Also, ∆DEF is given such that EF = 8cm and ∆DEF~∆ABC. Then, perimeter of ∆DEF is (a) 22.5cm (b) 25cm (c) 27cm (d) 30cm
CBSE | Class 10 | Exercise MCQ | Maths | RS Aggarwal | Triangles
In ∆ABC, it is given that AB = 9cm, BC = 6cm and CA = 7.5cm. Also, ∆DEF is given such that EF = 8cm and ∆DEF~∆ABC. Then, perimeter of ∆DEF is (a) 22.5cm (b) 25cm (c) 27cm (d) 30cm

Correct Answer: (d) 30 cm

Explanation:

Perimeter of ∆ABC = AB + BC + CA

=> 9 + 6 + 7.5

=> 22.5 cm

\begin{array}{l} \frac{{Perimeter(\Delta ABC)}}{{Perimeter(\Delta DEF)}} = \frac{{BC}}{{EF}}\\ \frac{{22.5}}{{ Perimeter(\Delta DEF)}} = \frac{{6}}{{8}}\\ Perimeter(\Delta DEF) = \frac{{22.5 \times 8}}{{6}}\\ Perimeter(\Delta DEF) = 30cm \end{array}

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