1/2" pipe is not half the size of 1".
small pond, remember "pie are square" and you'll see two 1/2" doesn't equal one 1".
Never seen a square pie, but if it is Blueberry, and with artery clogging toppings, I'm all in!
Simple way to think of circular area from any given size to another is:
If it's twice the diameter it would be 2x2=4, or 2^2, which equals 4 times the area.
3 times the diameter would be 3x3=9, or 3^2, which equals 9 times the area.
4 times the diameter would be 4x4=16, or 4^2, which equals 16 times the area.
The ^2 means that it is squared.
Every fractional size above the other is squared. 1.5 x the diameter is 1.5^2=2.25, which is 2.25 times the area.
See the pattern?
How about that square pie now?