Answer:
<h2>
The third: 5.32 cubic units</h2>
Step-by-step explanation:
R = 1.52
H = 2.2
π = 3.14

It's closed under addition. You can take any two natural numbers you want, add them up and you'll get some other natural number (eg: 3 and 5 ---> 3+5 = 8)
it's not closed under subtraction. Sure 5-3 = 2 is a natural number but 3-5 = -2 is not a natural number
so that leads us to the answer being choice B
Answer: i believe its a x=2