Anonymous
Anonymous asked in Science & MathematicsMathematics · 2 months ago

What’s the value of x and y?

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  • RR
    Lv 7
    2 months ago
    Favorite Answer

    You can work it out, step by step:

    The triangle on the right is an equilateral triangle, so all angles are 60 degrees

    The left hand triangle is an isosceles triangle. Its peak is 180 - 60 = 120 degrees (supplementary angle of 60 degrees)

    The other two angles in the isosceles triangle will be equal and will total 180 -120 = 60. Each one will be 60/2 = 30 degrees

    Now you have two simple equations:

    7y + 9 = 30

    7y = 21

    y = 3

    4x - 2 = 30

    4x = 32

    x = 8

    • RR
      Lv 7
      2 months agoReport

      Thank you!

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  • 2 months ago

    The triangle at the right side is an equilateral triangle, so its 3 angles are equal.

    blue = green = red = 60 °

    You can see that:

    red + yellow = 180

    yellow = 180 - red

    yellow = 120

    Whatever the triangle, the sum of the 3 angles is always 180 °.

    (4x - 2) + (7y + 9) + yellow = 180

    (4x - 2) + (7y + 9) = 180 - yellow

    (4x - 2) + (7y + 9) = 60 → as the triangle at the left side, is an isosceles triangle: (7y + 9) = (4x - 2)

    (4x - 2) + (4x - 2) = 60

    2.(4x - 2) = 60

    4x - 2 = 30

    4x = 32

    → x = 8

    Recall: (7y + 9) = (4x - 2)

    7y + 9 = 32 - 2

    7y = 21

    → y = 3

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  • 2 months ago

    4x - 2 = 30

    x = 8

    7y + 9 = 30

    y = 3

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  • David
    Lv 7
    2 months ago

    Both base angles of the isosceles triangle are 30 degrees;

    If 4x - 2 = 30 then x = 8

    If 7y + 9 = 30 then y = 3

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  • sepia
    Lv 7
    2 months ago

    120 + (4x - 2) + (7y + 9) = 180

    4x + 7y = 53

    4x - 2 = 30

    x = 8

    7y + 9 = 180 - 120 - 30 

    y = 3

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  • david
    Lv 7
    2 months ago

    4x - 2 = 30

      x = 8

    7y + 9 = 30

      y = 3

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