Question

The endpoints of a diameter of a circle are ( 3 , 9 ) and ( 3 , - 3 ). Find the equation of the circle.

Answer 1

Explanation:

distance between ( 3 , 9 ) and ( 3 , - 3 ) = 9 - (-3) = 12 because x is the same for both pts

12 is the diameter of circle so its radius = 12/2 = 6

center is in the middle: ( 3 , (9-3)/2 ) = ( 3, 3 )

so the circle's eqn is

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