What are the coordinates of the radius of the circle #x^2 + y^2 -8x -10y -8=0#?

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Answer 1 · 2016-02-05T09:27:18

The circle has a center i #C=(4,5)# and radius #r=7#

To find the coordinates of the center and the radius of a circle we have to transform its equation to form of:

#(x-a)^2+(y-b)^2=r^2#

In the given example we can do this by doing:

#x^2+y^2-8x-10y-8=0#

#x^2-8x+16+y^2-10y+25-8-16-25=0#

#(x-4)^2+(y-5)^2-49=0#

Finally:

#(x-4)^2+(y-5)^2=49#

From this equation we get the center and the radius.