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    a) Show that the centre of the circle with equation x² + y²= 6x + 8y is (3.4) and find the radius of the circle. (5)
    b)Find the exact length of the tangents from the point (10,0) to the circle. (4)

    I can do part (a) but cant do part (b). Any help appreciated.
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    if you know the center and the radius you can use pythag on the unknown length

    so work out the length fromt the radius to the point 10,0 then you know the distance of the radius, then use a^2 = b^2 +c^2 to work out the unkown distance
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    Draw a picture, make a right angled triangle from centre, to edge of circle (where the tangent is) and to point (10,0). Then its easier to see what the above method is telling you to do.
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    yh Thanks I get it now
 
 
 
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Updated: June 19, 2005
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