Foam thickness t = 3 cm on all faces. Outer dimensions = inner + 6 cm on each side.<br><br>
Outer length = 120 + 6 = 126 cm<br>
Outer width = 80 + 6 = 86 cm<br>
Outer height = 50 + 6 = 56 cm<br><br>
Outer volume = 126 × 86 × 56 = 606,816 cm&sup3;<br>
Inner volume = 120 × 80 × 50 = 480,000 cm&sup3;<br><br>
Foam volume = 606,816 − 480,000 = 126,816 cm&sup3;<br><br>
Final Answer: 126,816 cm&sup3;