How many integers between 200 and 300 are perfect squares?

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- December 12th 2009, 02:51 PMsri340perfect squares
**How many integers between 200 and 300 are perfect squares?** - December 12th 2009, 03:25 PMGusbob
We know 10 x 10 = 100.

Working from there:

11 x 11 = 121

12 x 12 = 144

13x 13 = 169

14 x 14 = 196

15x15 = 225 but that's over 200.

So there are four perfect squares between 100 and 200 (not inclusive of 100) - December 13th 2009, 01:23 AMaidan
- December 13th 2009, 03:20 AMBacterius
You can also use a progression.

Say , (note difference ).

How many terms between and ? :)

Start from the biggest square under , which is . Now many with can you fit in ?

Is there any sum of terms of with and starting from consecutive that fit into ? Sure ! We have , but we cannot fit , so there are only three perfect squares between and .

There ... must be a better way to explain this, though ..

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I know this solution is a bit*useless*and*boring*after the previous answers, but eh, this is worth a post :D