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Chapter 13 Class 9 Surface Areas and Volumes

Chapter 14 Class 9 StatisticsΒ β†’
Class 9
Important Questions for Exam - Class 9

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

Last updated at May 29, 2023 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? [π΄π‘ π‘ π‘’π‘šπ‘’ πœ‹= 22/7] Roller is of form cylinder Radius = π·π‘–π‘Žπ‘šπ‘’π‘‘π‘’π‘Ÿ/2 = 84/2 = 42 cm Area of roller = Curved surface of cylinder = 2Ο€rh = (2Γ—22/7Γ—42Γ—120) cm2 = 31680 cm2 Area of 1 revolution = Area of roller = 31680 cm2 Area of 500 revolution = 500 Γ— 31680 cm2 Area of playground = 15840000 cm2 = 15840000 Γ—1/(100 ) Γ—1/(100 )m2 = 1584 m2

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