Question

A circle has the equation $x^2+y^2=16$. How do you find the center, radius and the intercepts?

Answer 1

The standard form of the equation of a circle is
$(x-a{)}^2+(y-b{)}^2=r^2$
where $(a,b)$ are the coords of the centre and $r$, the radius.
$x^2+y^2=16$ is in this form
with $a=b=0$ and $r=4$
hence this circle has centre at the origin $(0,0)$ and radius $4$
The intercepts will therefore be $(\pm 4,0)$ and $(0,\pm 4)$.