You started out with 260, and increased to 430.
The amount you increased was (430 - 260) = 170
170 is (170/260) = <em>65.4%</em> of what you started with.
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Another way:
The new amount is (430/260) of the old amount.
430 / 260 = 1.654 = 165.4%
The original amount was 260.
You started with 100% of it.
You ended up with 165.4% of it.
That's an increase of 65.4% .
1: (pi)5^2 = 78.54 then multiply that by 11 and you get 863.94
2: (pi)13^2= 530.93 then multiply that by 8 and you get 47247.44
3. (pi)18^2= 1017.88 then multiply that by 22 and you get 22393.36
The compatible number is 7 (seven)