Well any number you add can be irrational need more information.
Answer:
It is an octagon if and only if it has eight sides.
Step-by-step explanation:
Here's one shortcut:
2.3×10^9=1000(2.3×10^6) because your adding 3 more zeros to 2300000
Answer is bottom left
1/2 inch per day and already planted 20 inches