Question 4 - Chapter 13 Class 9 Surface Areas and Volumes (Important Question)

Last updated at April 16, 2024 by

Ex 13.2, 4 - The diameter of roller is 84 cm and its length - Area Of Cylinder

 

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Question 4 The diameter of a roller is 84 cm and its length is 120 cm. It takes 500 complete revolutions to move once over to level a playground. Find the area of the playground in m2? [𝐴𝑠𝑠𝑢𝑚𝑒 𝜋= 22/7] Roller is of form cylinder Radius = 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟/2 = 84/2 = 42 cm Area of roller = Curved surface of cylinder = 2πrh = (2×22/7×42×120) cm2 = 31680 cm2 Area of 1 revolution = Area of roller = 31680 cm2 Area of 500 revolution = 500 × 31680 cm2 Area of playground = 15840000 cm2 = 15840000 ×1/(100 ) ×1/(100 )m2 = 1584 m2

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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 and Computer Science at Teachoo