Reflection

So we have an Exam in this class on the book Flatland.......haha ok old stuff

finding the center of Conics and the radius.

Steps:
1. The equation of a circle in standard form: (x-h)^2+(y-k)^2=r^2
the center=(h,k) and r=radius
2. If not in standard form, you must complete the square to put in standard form
3. Given the center and a point, you can use the distance formula to find the radius

Ex.: (x-3)^2+(y+7)^2
Center:(3,-7)
Radius:√19

Ex. with completing the square:
x^2+y^2-6x+4y-12=0
x^2-6x+__+4^2+4y+__=12
x^2-6x+9+4^2+4y+4=12+9+4
(x-3)^2+(y+2)^2=25
Center:(3,-2)
Radius:25

Does anyone know exactly what the exam is on in the book?