Question

The circle below is centered at the origin, and the length of its radius is 3. Write the equation for the circle.

Answer 1

Thanks so much needed help with this

Answer 2

Answer: $x^2+y^2=9$

Explanation:

A circle is the locus of points such that its distance from its center is constant. In our case, we have that the center of the circle is the origin, while the radius is 3. Thus, by the Pythagorean Theorem, the equation of the circle is $x^2+y^2=3^2=9$.