Equation of a circle..???

Question

The diameter of a circle has endpoints at (-3,-4) and (5,0). Find the equation of the circle. Could someone explain how to do this problem?

Answer 1

Mid point ( 1,- 2 )
r ² = (5 - 1) ² + (0 + 2) ²
r ² = 20
Centre (1 , - 2)
(x - 1)² + (y + 2)² = 20

Answer 2

We need two things
Distance from (-3,-4) to (5,0) to get the diameter
and the midpoint of that line.

Midpoint will be (-3+(5-(-3))/2, -4 + (0-(-4))/2) or (1, -2)

Distance is sqrt((5-(-3)^2 + (0-(-4))^2) or sqrt(64 + 16) or sqrt(80). Now this is the diameter, so radius is sqrt(80)/2 or 2sqrt(5)

Circle is:
(x-1)^2 + (y+2)^2 = 20

Answer 3

The basic circle equation on the origin is x^2 + y^2 = r^2. O.K just tried writing the equation but its unreadable. Basically X squared plus the x co-ordinate + y squared plus the y co ordinate = radius squared. I think. You know the radius (5-(-3))/2 Work the rest out :P