tolong jawab,buat besok dikumpulin, makasih :)

misal x = sisa karton bagian bawah

90/(90-5-x) = 60/(60-5-5)
90/(85-x) = 60/50
90/(85-x) = 6/5
90×5 = (85-x)6
450 = (85-x)6
450/6 = 85-x
75 = 85 -x
x = 85-75 = 10
jadi sisa karton bagian bawah = 10 cm