Nomor 1:

Lp = 6s²

Lp = 6 × La

Lp = 6 × 81

Lp = 486 cm²

Nomor 2:

Lp = (2× La) + (Ka × T)

Lp = (2 × ½ × a × t) + (jumlah semua sisi × T)

Lp = (2 × ½ × 12 × 16) + ((12 + 16 + 20) × 18)

Lp = (12 × 16) + (48 × 18)

Lp = 192 + 864

Lp = 1.056 cm²

Nomor 3:

Lp = 2πr (r + t)

Lp = 2 × 3,14 × 10 (10 + 28)

Lp = 6,28 × 10 × 38

Lp = 62,8 × 38

Lp = 2.386,4 cm²

Nomor 4:

Lp = (2(pt + lt)) + (pl)

Lp = (2(40 × 20) + (20 × 25)) + (40 × 20)

Lp = (2(800 + 500)) + 800

Lp = 2(1.300) + 800

Lp = 2.600 + 800

Lp = 3.400 cm²

Nomor 5:

L karton = 0,25 m² = 2.500

• Tentukan luas permukaan tabung

Lp = 2πr (r + t)

Lp = 2 × 3,14 × 8 (8 + 18)

Lp = 6,28 × 8 × 26

Lp = 1.306,24 cm²

• Bagilah antara luas karton dengan luas tabung

Sisa karton = 2.500 ÷ 1.306,24

= 1,91 cm²