standard_description: Identify when two expressions are equivalent (i.e., when the two expressions name the same number regardless of which value is substituted into them). For example, the expressions y + y + y and 3y are equivalent because they name the same number regardless of which number y stands for.
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