The equation of a circle centered at the origin (0, 0) and with a radius r is:
[tex]x^2+y^2=r^2[/tex]We are given the equation of a circle:
[tex]x^2+y^2=5[/tex]Comparing the above equation, we have that:
[tex]\begin{gathered} r^2=5 \\ \\ \text{ Therefore:} \\ \\ r=\sqrt{5} \end{gathered}[/tex]Thus:
[tex]\text{ The center of the circle is \lparen0, 0\rparen and its radius is }\sqrt{5}[/tex]