Jawab:
= 976 ⁴/₉ cm²

Penjelasan dengan langkah-langkah:

Diketahui
BALOK
p:l:t = 3:2:4

Panjang = 13 cm
Maka
13 = (3)/(3+2+4) × (p+l+t)
13 = 3/9 × (p+l+t)
p+l+t = 13 ÷ 3/9
p+l+t = 13 × 9/3
p+l+t = 13 × 3
p+l+t = 39 cm

Lebar = 2/(3+2+4) × (p+l+t)
Lebar = 2/9 × 39
Lebar = 26/3 cm

Tinggi = 4/(3+2+4) × (p+l+t)
Tinggi = 4/9 × 39
Tinggi = 52/3 cm

Luas permukaan =
2×(Panjang×(Lebar+Tinggi) + (Lebar×Tinggi)
= 2×(13×(26/3 + 52/3) + (26/3 × 52/3))
= 2×(13×(78/3) + (1352/9)
= 2×((1014/3) + (1352/9))
= 2×((3042/9) + (1352/9))
= 2×(4394/9)
= 8788/9
= 976 ⁴/₉ cm²

<(7o7)>