2*3*6
2*2*9
1*6*6
3*3*4
and many others
but the last hint “my oldest son is 4.5 feet tall" obviously 9 years old boy would be around 4-5 feet tall .... so 9*2*2 ... is possible ..!!
Akshay Ginodia And 9*4*1 is also possible
Hamza-Ul-Huda now i'm in a hurly burly ...!! i guess u are also correct ...!! ???