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Ex 3.1, 6 - Ex 3.1, 6 
If in two circles, arcs of the same length subtend angles 60° and 75° at the centre, fin - Arc length

Ex 3.1, 6 - Chapter 3 Class 11 Trigonometric Functions - Part 2

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Transcript

Ex 3.1, 6 If in two circles, arcs of the same length subtend angles 60° and 75° at the centre, find the ratio of their radii. We know that l = r θ There are 2 circle of different radius So, the radius be denoted by r1 and r2 Length of arc of Ist circle l = r1 θ = r1 × 60° = r1 × 60 × 𝜋/180 = r1 𝜋/3 It is given that arcs are of same length Hence Length of lst arc = length of llnd arc r1 × 𝜋/3 = r2 × 5𝜋/12 r1/𝑟2 = 5𝜋/12 × 3/𝜋 r1/r2 = 5/4 Hence r1 : r2 = 5 : 4 So, Ratio of radius = 5 : 4

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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.