Please explain how to solve the question.?

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  • iceman
    Lv 7
    3 years ago
    Favorite Answer

    Angle AEC = Angle DEB = 4x degrees

    Angle Formed by Two Intersecting Chords = 1/2(sum of intercepted arcs), so in this case:

    4x = 1/2(120 + 2x)

    4x = x + 60

    3x = 60

    x = 20 degrees

    4x = 80 degrees

    Angle AED = 1/2(360 - 2*80)

    = 1/2(360 - 160)

    = 1/2(200)

    Angle AED = 100 degrees

    Edit: Re: the comment/question: The name of formulas used?

    The first formula that was used to find the angles equating to 4x degrees, is driven by a theorem called:

    "Angles of intersecting chords" . You can read and review more examples in the link below:

    http://www.mathwarehouse.com/geometry/circle/angle...

    The second theorem that was use to find angle AED is simply the properties of vertical angles formed by 2 intersecting lines, for more information the please see the link below:

    http://www.mathopenref.com/anglesvertical.html

    I hope this helps.

    • Miriam3 years agoReport

      Thank you, did you use a formula to solve this, if so what is it called.

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  • 3 years ago

    You need to shut your eyes to solve the question.

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