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    hi guys; i CANNOT GET MY HEAD ROUND THIS UGLY QUESTION !!! so question is: The circle C has the equation
    x^2 + y^2 +10x - 8y +k =0,
    where k is a constant.
    Given that the point with coordinates (−6, 5) lies on C,
    (a) find the value of k, (2)
    (b) find the coordinates of the centre and the radius of C. (3)
    A straight line which passes through the point A (2, 3) is a tangent to C at the point B.
    (c) Find the length AB in the form k 3 .

    part A B is fine for me but part c is driving me insane! pls pls pls help !!
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    Draw a triangle ABX where X is the centre. You know the length of XB, you can work out the length of AX. And this should allow you to find AB
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    Draw a diagram, you should notice that it forms a right angle triangle with one side being the radius, the other being AB and the other being A-center, you can find the length of A-center and you know the radius, do some pythagoras and there you go ;p
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    Yeah, find the length between the centre and A (because you know both of these co-ordinates), and the length between the centre and point B, which is just the radius, then you have yourself a right angled triangle with AB as the missing side so you can just use Pythagoras
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    thank you !!
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    I can't do part c) ? Anyone


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    Bump


    Posted from TSR Mobile
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    As already stated, draw a diagram and you should end up with a right angled triangle, then use pythagoras to solve for the unknown side
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    I have drawn but I can't find it


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    Name:  ImageUploadedByStudent Room1464117575.836389.jpg
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    Posted from TSR Mobile
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    radius is root 2 so use pythagoras
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    (Original post by Kawaii289)
    radius is root 2 so use pythagoras
    Thank you, I didn't realise


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    no problem
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    (Original post by Fish40)
    Thank you, I didn't realise


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    remember circle theorems is in the specification so remember those "laws".
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    Can someone leave the answers of all the parts? ; a) b) and c) ?? PLEASE!
 
 
 
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