Question

Write an equation of the circle with center (3, -6) and radius 5.

Answer 1

answer

(x-3)^2 + (y+6)^2 = 25

set up equation

the equation of a circle is (x - centerx)^2 + (y - centery)^2 = r^2

values

from the point (3,6) we know that centerx = 3 and centery = -6

since the radius is 5, r^2 = 5^2 = 25

plug in values

now that we have all the values, we plug them into (x - centerx)^2 + (y - centery)^2 = r^2

(x - centerx)^2 + (y - centery)^2 = r^2

(x - 3)^2 + (y-(-6))^2 = 25

(x-3)^2 + (y+6)^2 = 25

Answer 2

Answer:

formula for a circle: (x-h)^2 + (y-k)^2 = r^2, where (h,k) is the center and r is the radius.

1. Plug in center coordinates into formula

(x-3)^2 + (y-(-6))^2 = r^2

2. Plug in radius value

(x-3)^2 + (y-(-6))^2 = 5^2

3. Simplify:

(x-3)^2 + (y+6)^2 = 25