Problem Solving (PS) | Which of the following is a perfect square?

The solutions above seem way complicated to follow, so I went with this method:Identifying the nearest perfect square

(a) 649
nearest perfect square is 625 = 25^2
26^2 is obviously the next perfect square and that's significantly larger -->eliminate

(b) 961
30^2 = 900
so try 31^2 = 961
Perfect. Can stop here, but will work through the others

(c) 1664 It's fairly easy to divide this number down to its prime factors and then examine to prime factors to realise they aren't
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