∆ABC is such that AB = 3 cm, BC = 2cm, CA = 2.5 cm. If ∆ABC ~ ∆DEF and EF = 4 cm, then perimeter of ∆DEF is

(a) 7.5 cm   (b) 15 cm   (c) 22.5 cm   (d) 30 cm

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Question 16 - Sample paper Maths Class 10 - 2022 Boards - Standard.jpg


Transcript

Question 16 ∆ABC is such that AB = 3 cm, BC = 2cm, CA = 2.5 cm. If ∆ABC ~ ∆DEF and EF = 4 cm, then perimeter of ∆DEF is (a) 7.5 cm (b) 15 cm (c) 22.5 cm (d) 30 cm Since ∆ ABC ~ ∆ DEF Sides will be proportional AB/DE=𝐵𝐶/𝐸𝐹=𝐴𝐶/𝐸𝐹 Putting values 3/DE=2/4=2.5/𝐸𝐹 3/DE=1/2=2.5/𝐸𝐹 𝟑/𝑫𝑬=𝟏/𝟐 DE = 2 × 3 DE = 6 cm 𝟏/𝟐=(𝟐.𝟓)/𝑬𝑭 EF = 2 × 2.5 EF = 5 cm Now, Perimeter of Δ DEF = DE + EF + DF = 6 + 5 + 4 = 15 cm So, the correct answer is (b)

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.