Write an equation for each circle described.
Center at origin,radius is 3.
I'm stuck.aren't I suppose to be given an endpoint for me to be able to
use the midpoint formula to find the center?
I need help please...oh that's the only thing they give me.
No, you don't necessarily need an endpoint to find the equation of a circle. In this case, you are given that the center of the circle is at the origin (0,0) and the radius is 3.
The general equation of a circle with center (h, k) and radius r is given by:
(x - h)^2 + (y - k)^2 = r^2
Since the center is at the origin (0,0), the equation becomes:
x^2 + y^2 = r^2
Substituting the given radius of 3, the equation of the circle is:
x^2 + y^2 = 3^2
x^2 + y^2 = 9
So the equation of the circle with a center at the origin and a radius of 3 is x^2 + y^2 = 9.