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Ex 3.1, 5 In a circle of diameter 40 cm, the length of a chord is 20 cm. Find the length of minor arc of the chord. Given Diameter = 40 cm Radius = r = 20 cm We need to find length of minor arc of the chord. Thus, we use formula θ = 𝒍/𝒓 to find length of arc In figure, AB = r = 20 cm AC = r = 20 cm BC = Length of chord = 20 cm So, AB = AC = BC = 20 cm Since all sides of Δ ABC are equal Hence, Δ ABC is equilateral Since in equilateral triangle, all angles are 60° Hence, ∠ BAC is 60° ∴ 𝜽 = 60° Finding Angle in Radians Now, θ = 60o = 60o × 𝜋/(180°) = 𝝅/𝟑 Now, Putting values in formula "θ = " 𝒍/𝒓 𝝅/𝟑 =𝒍/𝟐𝟎 𝑙 = 20 × (𝜋 )/3 𝒍 = (𝟐𝟎𝝅 )/𝟑 cm

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Davneet Singh

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.