I would assume that you are asking for the area of this table, the formula is
A= [tex] \pi r^{2} [/tex]. The radius is half of the diameter, so we divide 5 by 2, which equals 2.5
2.5 x 2.5 = 6.25
So the answer is 6.25[tex] \pi [/tex] or 19.625
(I used 3.14 for pi)