persegi panjang luas = p x l = 3.850 (15 + l) x l = 3.850 15l + l² - 3.850 = 0 l² + 15l - 3.850 = 0 (l + 70) (l - 55) = 0 l = 70 (tidak memenuhi karena negatif) atau l = 55 (memenuhi)
p = l + 15 p = 55 + 15 p = 70 m
keliling = 2 x (p + l) keliling = 2 x (70 + 15) keliling = 2 x 85 keliling = 170 m
Verified answer
Bab Bangun DatarMatematika SMP Kelas VIII
persegi panjang
luas = p x l = 3.850
(15 + l) x l = 3.850
15l + l² - 3.850 = 0
l² + 15l - 3.850 = 0
(l + 70) (l - 55) = 0
l = 70 (tidak memenuhi karena negatif) atau l = 55 (memenuhi)
p = l + 15
p = 55 + 15
p = 70 m
keliling = 2 x (p + l)
keliling = 2 x (70 + 15)
keliling = 2 x 85
keliling = 170 m
biaya = 170 x 15.000
biaya = Rp 2.550.000,00