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    Problem solved thanks!
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    (Original post by 83607)
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    The answer is also meant to be in exact surds. Really need help on this thanks!
    By symmetry the centre is going to be on the vertical midline.

    Then consider which four corners is the circle going to touch? Again there will be a vertical symmetry.
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    Wouldnt it be the bottom two corners and the top two corners of the grid extending from the middle?
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    (Original post by 83607)
    Wouldnt it be the bottom two corners and the top two corners of the grid extending from the middle?
    The very top two, and the bottom two furthest from the midline, yes. So, those four points will lie on the circle. Can you now work out the radius?
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    Can someone post the correct answer as a spoiler please, as I am curious to see if i got it right
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    (Original post by Snasher350)
    Can someone post the correct answer as a spoiler please, as I am curious to see if i got it right
    Assuming the edges are of unit length.

    I make the radius:
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    \dfrac{\sqrt{130}}{6} units
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    (Original post by Snasher350)
    Can someone post the correct answer as a spoiler please, as I am curious to see if i got it right
    Finally got it pretty sure its root130 /6
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    (Original post by 83607)
    Finally got it pretty sure its root130 /6
    Agreed - corrected mine!
 
 
 
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