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I have one question.

I have given 5 coordinates:

0 0

2 0

1 1

1 -1

3 -1

The question is how many right angles can I create with these coordinates?

I know one way out, but it is pretty complicated.

C_{5}^{2}=5!/(2!*3!)=5*4*3!/(2!*3!)=10

And try every single combination (finding the sides of the triangles, there are 10 of them). Is there any simpler way?

Thanks in advance.

Regards.

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# How many right triangles can you create with given coordinates?

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