Question 148393
1. graph the circle whose equation is     x squared + y squared = 64.  what is its radius? 
2. what do the equations  x squared + y squared = 1 and   x squared + y squared = k all have in common? how do they differ?
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1. I don't think I can do graphs here, but
{{{x^2 + y^2 = 8^2}}} is a circle about the origin of radius 8.
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2. Since there are no other terms, their centers are the origin.
Their radii are different, {{{sqrt(1)}}} and {{{sqrt(k)}}}