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Ex 12.2, 3 - The length of minute hand of a clock is 14 cm - Ex 12.2

Ex 12.2, 3 - Chapter 12 Class 10 Areas related to Circles - Part 2

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Ex 12.2, 3 The length of the minute hand of a clock is 14 cm. Find the area swept by the minute hand in 5 minutes. Minute hand completes full circle degree in one hour Swept by minute hand in 1 hour (ie 60 minutes ) = 360° Swept by minutes hand in 1 minutes = 360/60 = 6° Swept by minute hand in 5 minutes = 6° ×5 = 30° Hence θ = 30° , r = 14 cm Area swept by minutes hand = Area of sector = θ/360×πr2 = 30/360×22/7×(14)2 = 1/12×22/7×14×14 = 1/12×22/1×2×14 = 154 cm2 Hence area swept by minute hand in 5 minutes = 154 cm2

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.