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Figure 105 : Equilateral triangle and circle

    Equilateral triangle and circle


  • Q01 | - Diagram
  • Q02 | - Equilateral triangle and circle
  • Q03 | - Questions


    Q01. Diagram


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    Q02. Equilateral triangle and circle

    Construction
    • Draw an equilateral triangle
    • Draw 1st circle inscribed triangle
    • draw 2nd circle tangent circle and two sides
    • draw 3rd circle tangent 2nd circle and two sides
    • Find the area of the 3rd circle

    Find area of smallest circle
    • Let each side be 1
    • Height of triangle h = Sqr(1 + (1/2)^2) = Sqr(3)/2
    • Radius of 1st circle r1 = h/3 = Sqr(3)/4
    • Radius of 2nd circle r2 = (r1)/3 = Sqr(3)/(3*4)
    • Radius of 3rd circle r3 = (r2)/3 = Sqr(3)/(3*3*4) = Sqr(3)/36
    • Hence area of 3rd triangle = pi*(r3)^2 = 3*pi/(36^2) = 0.0023148

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    Q03. Questions
    Questions
    • 1. Find area of 4th circle which tangent 3rd circle and two sides

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