Question

What is the equation of a circle with a center origin and radius 15?

Answer 1

The standard form of a circle is
`(x-h)^2+(y-k)^2=r^2`, where h and k are the coordinates of your center. Your center is (0, 0) and your radius, r, is 15. We will fill in accordingly.
`(x-0)^2+(y-0)^2=15^2`. That simplifies down to
`x^(2) +y^2=225`. And you're done!