Question 810651
Find the equation of a circle having it's diameter the line segment joining the points (3,7) and (-5,1). 
-----
Find the midpoint (center of the circle).
x = (3+-5)/2 = -1
y = (7+1)/2 = 4
-----
Center is (-1,4)
---------------------
Find the radius (distance from end point to center):
r = sqrt[(3--1)^2+(7-4)^2] = sqrt[16+9] = 5
---------
Circle Equation:
(x+1)^2 + (y-4)^2 = 5^2
=============================
Cheers,
Stan H.
=============================