Write the equation of the circle: Center at P (2, - 1) and a diameter of 10m

An equation of the circle is

(x-h) ² + (y-k) ² = r²,

where (h, k) are coordinates of the center of the circle, and r is a radius of the circle.

We have h=2, k = - 1, and radius r=diameter/2=10/2=5.

The equation of our circle is

(x-2) ² + (y+1) ²=25