Question

What is the equation of a circle with center (2,-5) and radius 4?

Answer 1

Answer:

(x - 2)² + (y + k)² = 4²

Step-by-step explanation:

To answer this, we insert the given into (center x-coordinate 2, center y-coordinate -5, radius 4) into the general formula for a circle with center at (h, k) and radius r:  (x - h)² + (y - k)² = r²  →  (x - 2)² + (y + k)² = 4²

Answer 2

The GENERAL equation for EVERY circle with its center at (A, B) and a radius of R is

(x - A)²  +  (y - B)²  =  R² .

So if you just stuff in the numbers given in this question, the equation of THIS circle is

(x - 2)²  +  (y + 5)²  =  16