before the appreciation :
1C$ -> 0.433 pounds
?C$-> 1 pound we find : ?=1/0.433 = 2.30947 C$
after the appreciation the dollar is more valuable then before compared to the pound so we get less dollars for our 1 pound. We get exactly 0.0017 less dollars so
1 pound -> 2.30947 - 0.0017 C$
so 1 pound -> 2.30777 C$
but we want
? pounds -> 1C$ having
1 pound -> 2.30777 C$ we find : ? = 1/2.30777 = 0.4333 pounds per 1C$.
Where I used "?" as is my unknown.
How do you see the appreciation? Well appreciation means more money so before 1C$ gave us 0.433 pounds now it gives 0.4333 becaused it raised in value compared to the pound. It is 0.0003 pounds more.