# What Is a Circle

What is a circle? Any circle is a geometric figure. You can get it in the geometric plane with the canonical inequality:

x^{2} + y^{2} ≤ r^{2}

where r - is radius of the circle, D = 2r - is diameter of the circle

or

(x - m)^{2} + (y - n)^{2} ≤ r^{2}

where A(m;n) - is the centre

This is an inequality of the circle with the centre in the point A(m;n).