Question 1183671
What is an equation that relates all the x- and y- coordinates of points that
lie on ⊙M with a radius of 5, which is centered at the origin? <pre>

{{{drawing(400,400,-5.9,5.9,-5.9,5.9,locate(1.65,2.15,5),locate(2.2,.52,x),
locate(3.33,1.7,y),locate(3.8,3.73,"P(x,y)"),
red(line(0,0,3.7,3.363034344),line(3.7,3.363034344,3.7,0)),
grid(1), circle(0,0,5) )}}}

Let P(x,y) be an arbitrary point on circle M.  The right triangle with
legs x and y, hypotenuse 5, and vertex P(x,y) can be drawn anywhere on the
circle.  So the equation that holds for all points on the circle is the
Pythagorean theorem, using x and y for the legs and 5 for the hypotenuse.

x<sup>2</sup> + y<sup>2</sup> = 5<sup>2</>

or

x<sup>2</sup> + y<sup>2</sup> = 25

Edwin</pre>