A vertical stick 20m long casts a shadow 10m long on the ground. At the same time a tower casts a shadow 50m long. What is the height of the tower?

(a) 30m   (b) 50m   (c) 80m   (d) 100m

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Transcript

Question 39 A vertical stick 20m long casts a shadow 10m long on the ground. At the same time a tower casts a shadow 50m long. What is the height of the tower? (a) 30m (b) 50m (c) 80m (d) 100m Since the triangles are similar Their sides are proportional (𝑯𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒕𝒊𝒄𝒌)/(𝑳𝒆𝒏𝒈𝒕𝒉 𝒐𝒇 𝒔𝒉𝒂𝒅𝒐𝒘 𝒐𝒇 𝒔𝒕𝒊𝒄𝒌)=(𝑯𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝑻𝒐𝒘𝒆𝒓)/(𝑳𝒆𝒏𝒈𝒕𝒉 𝒐𝒇 𝒔𝒉𝒂𝒅𝒐𝒘 𝒐𝒇 𝑻𝒐𝒘𝒆𝒓) 20/10=(𝑯𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝑻𝒐𝒘𝒆𝒓)/50 2 =(𝐻𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑇𝑜𝑤𝑒𝑟)/50 2 × 50 = Height of tower Height of tower = 100 m So, the correct answer is (d)

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Davneet Singh

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.