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Ex 11.3, 16 - How many times a wheel of radius 28 cm must rotate

Ex 11.3, 16 - Chapter 11 Class 7 Perimeter and Area - Part 2
Ex 11.3, 16 - Chapter 11 Class 7 Perimeter and Area - Part 3

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Ex 11.3, 16 How many times a wheel of radius 28 cm must rotate to go 352 m? (π‘‡π‘Žπ‘˜π‘’ πœ‹=22/7) Circumference of wheel In 1 rotation, wheel travels distance = Circumference Therefore, Number of rotations = (π·π‘–π‘ π‘‘π‘Žπ‘›π‘π‘’ π‘‘π‘Ÿπ‘Žπ‘£π‘’π‘™π‘™π‘’π‘‘)/(πΆπ‘–π‘Ÿπ‘π‘’π‘šπ‘“π‘’π‘Ÿπ‘’π‘›π‘π‘’ π‘œπ‘“ π‘€β„Žπ‘’π‘’π‘™) Circumference of wheel Radius of wheel = r = 28 cm Circumference of wheel = 2πœ‹r = 2 Γ— 22/7 Γ— 28 = 2 Γ— 22 Γ— 4 = 44 Γ— 4 = 176 cm = 176 Γ— 1/100 m = 1.76 m ("1 cm = " 1/100 " m" ) Now Given, Distance travelled = 352 m Number of rotations = (π·π‘–π‘ π‘‘π‘Žπ‘›π‘π‘’ π‘‘π‘Ÿπ‘Žπ‘£π‘™π‘™π‘’π‘‘)/(πΆπ‘–π‘Ÿπ‘π‘’π‘šπ‘“π‘Ÿπ‘’π‘›π‘π‘’ π‘œπ‘“ π‘€β„Žπ‘’π‘’π‘™) ∴ Number of rotations = 352/1.76 = 352/176 Γ— 100 = 176/88 Γ— 100 = 88/44 Γ— 100 = 2 Γ— 100 = 200 ∴ Wheel rotates 200 times

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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.