Geometry Math Help???

Question

How do you find the radius?

I have to find an equation.

Question: The circle has center (0,6) and passes through point (6,14).

I know the equation is (x+2)2 + (y+4)2, but don't know the radius.

Answer 1

The circle with center (0,6) will look like this:

(x-0)² + (y-6)²= r²

You know the circle passes through (6,14), so plug these in for x and y to find r

(6-0)²+(14-6)²=r²

6²+8²=r²

36+64=r²

100=r²

r=10

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