Question

What is the equation of the circle graphed on the coordinate plane? answers: 1) (x – 2)2 + (y + 1)2 = 4 2) (x + 1)2 + (y – 2)2 = 16 3) (x – 2)2 + (y + 1)2 = 16 4) (x + 2)2 + (y – 1)2 = 16

Answer 1

3) (x – 2)^2 + (y + 1)^2 = 16

Explanation:

Equation of circle:

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

where (h, k) is the center, and r is the radius.

From the graph, we see the center is at (2, -1), so h = 2, and h = -1.

The radius is 4, so r = 4.

The equation is

(x - 2)^2 + (h - (-1))^2 = 4^2

(x - 2)^2 + (h + 1)^2 = 16