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

Transcript

Ex 11.3, 4 A gardener wants to fence a circular garden of diameter 21m. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the cost of the rope, if it costs Rs 4 per meter. (๐‘‡๐‘Ž๐‘˜๐‘’ ๐œ‹=22/7) Since the gardener makes two rounds of the fence Thus, Length of rope required = 2 ร— Circumference of circular garden Diameter = 21 m Radius = r = ๐ท๐‘–๐‘Ž๐‘š๐‘’๐‘ก๐‘’๐‘Ÿ/2 = 21/2 m Circumference of circular garden = 2๐œ‹r = 2 ร— 22/7 ร— 21/2 = 22/7 ร— 21 = 22 ร— 3 = 66 m Now, Length of rope required = 2 ร— Circumference of circular garden = 2 ร— 66 = 132 m Now, we also need to find cost of rope, Given, Cost of 1 m rope = Rs 4 Cost of 132 m rope = Rs 4 ร— 132 = Rs 528 โˆด It would cost Rs 528 to fence the garden

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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.