You could look at each dimension seperately:
1.) How often does 1.5 inches fit into 22 feet?
1.5 inches=0.125 feet (looked up the conversion)
22 feet/0.125 feet= 176
2.) How many balls fit into 16 feet? same thing :)
16 feet/0.125 feet=128
3.) How many balls fit into 9 feet?
9 feet/0.125 feet=72
Then you multiply them all out because there are 72 layers of 176x128 balls, right?
9*176*128=1622016 balls overall
Hope that helped ;)
