Question

Help! How do you write equations of circles?
A circle has a diameter with endpoints (3, -2) and (9, -8).

What is the equation of the circle?


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

Answer 1

first find the midpoint of the line joining the 2 points

if the midpoint is (a,b) the equation is

(x - a)^2 + (y - b)^2 = r^2

Answer 2

do you know the formula for the midpoint?

Answer 3

Mid.= 3+9/2 , -2+-8/2
= 12/2 , -10/2
= 6,-5
= (x-6)^2 + (y+5)^2= R^2
Correct? Answer=D. ?

Answer 4

yes

Answer 5

Thanks For Your Help! (:

Answer 6

yw