Question 1047416
Midpoint Pt(x,y):  ( {{{(x[1] + x[2])/2}}}, {{{(y[1] + y[2])/2  )}}})
Endpoints of a diameter: 
(0, 0), 
(6, 8)   C( 3, 4)
(x-3)^2 + (y-4)^2 = r^2
Substitute (0.0) which is on this circle
9 + 16 = 25 = r^2, r = 5

the standard form of the equation of the circle 
{{{(x-3)^2 + (y-4)^2 = 25 }}}