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CBSE Class 10 Sample Paper for 2019 Boards

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Question 29 - CBSE Class 10 Sample Paper for 2019 Boards - Solutions of Sample Papers for Class 10 Boards

Last updated at Oct. 1, 2019 by

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

Transcript

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 is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.