How do you find the equation of the circle given center:(0,0) radius: 2 square root of 7?

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Answer 1 · 2016-10-16T08:02:42

The equation of a circle with center $(a, b)$ $(a, b)$ and radius $r$ $r$ is:

${(x - a)}^{2} + {(y - b)}^{2} = r^{2}$ $(x-a)^2+(y-b)^2=r^2$

For this problem $a = 0, b = 0, r = 2 \sqrt{7}$ $a=0,b=0,r=2sqrt(7)$

Then the equation is:

${(x - 0)}^{2} + {(y - 0)}^{2} = {(2 \sqrt{7})}^{2}$ $(x-0)^2+(y-0)^2=(2sqrt(7))^2$ , that is:

$x^{2} + y^{2} = 4 \cdot 7$ $x^2+y^2=4*7$

So the equation is: $x^{2} + y^{2} = 28$ $x^2+y^2=28$