Original volume = 12 × 8 × 36 = 3456 cm&sup3;.<br><br>New length = 12 × 2 = 24 cm.<br>New width = 8 × 3 = 24 cm.<br>New volume (same) = 24 × 24 × h = 3456.<br><br>h = 3456 ÷ (24 × 24) = 3456 ÷ 576 = 6 cm.<br><br>Final Answer: 6 cm