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Question 29

The radii of circular ends of a bucket of height 24 cm are 15 cm and 5 cm. Find the area of its curved surface.

The radii of circular ends of a bucket of height 24 cm are 15 cm and

Question 29 - CBSE Class 10 Sample Paper for 2019 Boards - Part 2
Question 29 - CBSE Class 10 Sample Paper for 2019 Boards - Part 3

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Question 29 The radii of circular ends of a bucket of height 24 cm are 15 cm and 5 cm. Find the area of its curved surface. Here, the bucket is in the shape of a frustum Where h = height = 16 cm r1 = radius of upper end = 20 cm r2 = radius of lower end = 8 cm We need to find its Curved Surface Area Curved Surface Area of frustum = πœ‹(π‘Ÿ1+π‘Ÿ2)𝑙 We need to find l We know that 𝑙 = √(β„Ž2+(π‘Ÿ1βˆ’π‘Ÿ2)2) 𝑙 = √(242+(15βˆ’5)2) 𝑙 = √(242+102) 𝑙 = √(576+100) 𝑙 = √676 𝑙 = √(γ€–26γ€—^2 ) 𝑙 = 26 cm Now, Curved surface area of frustum = πœ‹(π‘Ÿ1+π‘Ÿ2)𝑙 = πœ‹(15+5)Γ—26 = 22/7Γ—20Γ—26 = (440 Γ— 26)/7 = 11440/7 = 1634.28 cm2 ∴ Curved surface area of frustum = 1634.28 cm2

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.