Tìm [,]
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cạnh hình vuông lúc chưa giảm là:
114,4:4 = 28,6(cm)
cạnh hình vuông lúc giảm là:
28,6-(28,6x20%)=22,88(cm)
chu vi hình vuông lúc giảm cạnh là:
22,88x4=91,52(cm)
