The area formula for a circle is
[tex]a = \pi(r)^{2} [/tex]
when r is radius.
The circumference formula is
[tex]c = 2(\pi)r[/tex]
Since you have the circumference, you can plug it in and solve for the circle's radius.
[tex]48 = 2(\pi)r[/tex]
[tex]24 = \pi(r)[/tex]
[tex] \frac{24}{\pi} = r [/tex]
Now that you have r, you can plug it into the area formula and find the area.
[tex]a = \pi( \frac{24}{\pi} )^{2} [/tex]
[tex]a = (24)^{2} [/tex]
[tex]a = 576[/tex]