The equation of the circle is may be expressed as,
(x - h)² + (y - k)² = r²
where h and k are the abscissa and ordinates of its center, respectively, and r is radius. Substituting the given values to the equation above,
(x - 5)² + (y - 3)² = 4²
Simplifying further the equation gives,
x² + y² - 10x - 6y + 18