standard_description: Relate the domain of a function to its graph and, where applicable, to the quantitative relationship it describes.  For example, if the function h(n) gives the number of person-hours it takes to assemble n engines in a factory, then the positive integers would be an appropriate domain for the function.
problem_activity: Problem 1
Write an equation that models each point’s distance from the center of the circle, point
$$A$$
.
[IMG]
Problem 2
A circle has a center at the origin and contains the point (
$$2, \space \sqrt{5}$$
).
Write an equation of the circle.
Identify the radius of this circle.
Name two other points that lie on this circle.


aligns: no