we know that
the standard form of the equation of the circle is
where
(h,k) is the center of the circle
r is the radius of the circle
In this problem we have
<u>Convert to standard form</u>
Group terms that contain the same variable, and move the constant to the opposite side of the equation
Complete the square twice. Remember to balance the equation by adding the same constants to each side.
Rewrite as perfect squares
the center of the circle is
the radius of the circle is
therefore
<u>the answer is</u>
the radius of the circle is
