Need some help. how do you find the equation of a circle with endpoints of the diameter at (-1,1) and (7,9)?

1 Answer
May 11, 2018

(x-3)^2 + (y-5)^2 = 32(x3)2+(y5)2=32

Explanation:

Urgent!

The center is the midpoint of the diameter:

(a,b) = ({-1 + 7}/2, {1+9}/2 ) = (3,5)(a,b)=(1+72,1+92)=(3,5)

The squared radius is the squared distance from the center to either endpoint:

r^2 = (3 - -1)^2 + (5-1)^2 = 32 r2=(31)2+(51)2=32

The general equation for a circle with center (a,b)(a,b) and radius rr is

(x-a)^2 + (y-b)^2 = r^2(xa)2+(yb)2=r2

(x-3)^2 + (y-5)^2 = 32(x3)2+(y5)2=32