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  1. Chapter 11 Class 7 Perimeter and Area
  2. Serial order wise

Transcript

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
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.