# POLQ 2 | Lesson 2 | Watch (Application of Completing the Square)

Completing the square is used to find the radius and center of circles. The standard form for a circle is $$ax^2 + by^2 + cx + dy + e =0$$. To find the radius and center of the circle the equation will need to be in the form $$(x-h)^2 + (y-k)^2 = r^2$$ where center is ($$h,k$$) and the radius is $$r$$.

Use this link to watch the video to help with the next task:

Features of a circle from its expanded equation | Khan Academy