Question

Identify the equation of the circle that has its center at (9, 12) and passes through the origin.

Answer 1

(x-9)^2 +(y-12)^2 = 225

Explanation:

First find the length of the radius

If is the distance from the center to the point

d = sqrt( (x2-x1)^2 + (y2-y1)^2 )

= sqrt( (0-9)^2 + (0-12)^2)

= sqrt ( 81+144)

= sqrt(225)

= 15

The equation for a circle is

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

(x-9)^2 +(y-12)^2 = 15^2

(x-9)^2 +(y-12)^2 = 225