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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: Tứ giác ABCD có Â=60°;B=100° C=70° thì D=?

Toán Lớp 8: Tứ giác ABCD có Â=60°;B=100° C=70° thì D=?

Comments ( 2 )

  1. Answer
    $\text{Ta có:}$ \hat{A} + \hat{B} + \hat{C} + \hat{D} = 360^o $\text{(tổng 4 góc trong tứ giác)}$
    => 60^o + 100^o + 70^o + \hat{D} = 360^o
    => 160^o + 70^o + \hat{D} = 360^o
    => 230^o + \hat{D} = 360^o
    => \hat{D} = 360^o – 230^o
    => \hat{D} = 130^o
    $\text{Vậy}$ \hat{D} = 130^o

  2. Tổng 4 góc trong 1 tứ giác bằng 360^o
    => hatA +hatB +hatC +hatD =360^o
    => hatD =180^o -(hatA +hatB +hatC +hatD) = 180^o -(60^o +100^o +70^o) = 360^o -230^o = 130^o

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222-9+11+12:2*14+14 = ? ( )