Write the equation of a circle with center at the origin and radius 6

Question

Write the equation of a circle with center at the origin and radius 6

Answer 1

An equation of the circle with center (h,k) and radius r is 

     (x-h)² + (y-k)² = r^2.

 

So, if the center is (0,0) and the radius is 6, an equation of the circle is:          (x-0)² + (y-0)² = 6².

 

Simplifying, we get:  x² + y² = 36