Circle formula

Question

I know that the standard circle formula or equation is

 

(x - h)^2 + (y - k)^2=r^2

What do h, k, x and y in the formula represent? What do they tell me about the circle?

Answer 1

The point (h,k) is the origin of the circle and in the formula they are the translation back to the point (0,0). X and Y represent the inputs (X) and the outputs (Y) for the formula. For each inputs (x) we will get 2 outputs which are the higher and lower points on the circle (y).

Answer 2

Circal 21 inch