Answer
The equation:
$x^2+y^2=144$
Represents a circle of radius 12.
Work Step by Step
The equation:
$x^2+y^2=144$
Has the form $x^2+y^2=r^2$, which represents a circle of radius r.
By making $r^2 = 144 $ you can find the radius of the circle which is:
$r^2 = 144 $
$r=\sqrt {144}$
$r=12$
