Find the equation of the circle in standard form for the given center (h,k) and radius r: (h,k)=(0,0), r=4

Question

Find the equation of the circle in standard form for the given center (h,k) and radius r: (h,k)=(0,0), r=4

Answer 1

Doubtless you know the standard form's equation (involving x-k, y-k & r).

You have all of the data i.e. h, k, r, at hand, so just substitute!

Answer 2

 

The base equation for a circle centered at (h, k) is:

 

     (x - h)² + (y - k)² = r²

 

Substituting (0, 0) for (h, k). and 4 for the radius,

 

     (x - 0)² + (y - 0)² = 4²

     

     x² + y² = 4²