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k = 2 x (p + l) = 68
p + l = 68/2
p = 34 - l
luas = p x l = 240
(34 - l) x l = 240
34 - l^2 = 240
l^2 - 34 + 240 = 0
(l - 10) (l - 24) = 0
l = 10 m atau l = 24 m
p = 34 - l
p = 34 - 10 = 24 m
p = 34 - 24 = 10 m
karena p > l
maka, p = 24 m