Matematika

Pertanyaan

perhatikan gambar di samping, jika keliling ∆ABC = 40 , maka luas ∆ABC = ..
perhatikan gambar di samping, jika keliling ∆ABC = 40 , maka luas ∆ABC = ..

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2 Jawaban

  • 40 = (x+5) +(x+7)+8
    40 =2x +12+8
    40 =2x+20
    40-2 = 2x
    20=2x
    10 =x

    AB= x+5
    AB= 10+5
    =15 (t)

    luas segitiga = a x t :2
    = 8 × 15 : 2
    = 60
    jawabannya c

  • (x+5)+(x+7)+8=40 cm
    2x+20=40 cm
    2x=40-20
    2x=20
    x=10
     
    t=x+5=10+5=15 cm

    luas=a*t/2
          =8*15/2
          =60 cm
    (c)

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