Question

How can i do this ?

Answer 1

The standart form for the equation of a circle is:

$(x-a)^2+(y-b)=r^2$

Where $(a,b)$ is the center of a circle and r is the radius.

So, in our case:

$a=3, b=5, r^2=25\Rightarrow a=3,b=5,r=5$

$(3,5)$ is the center. And $r=5$ is the radius.