Gimna caranya plissss bntu​

Luas kart0n
= luas total – luas foto
= 30×40 – (40-3-5)x(30-3-3)
= 1200 – (32)(24)
= 432m²

Sisa karton Bagian bawah
40/30 = (40-3-x)/(30-3-3)
40 x 24 = (37 – x) 30
960/30 = 37 – x
32 = 37 – x
x = 5 cm

Luas Karton yang Tidak Tertutup
= (30 x 40) – (40-3-5) x (30-3-3)
= 1.200 – 32 x 24
= 1.200 – 768
= 432 cm²