Answer
100 $cm^{2}$
Work Step by Step
Given apothem of length 5 cm
apothem is the perpendicular distance from the center to the side of the lengths.For square s= 2a
As we know the area of the square of side s is A = $s^{2}$
put s = 2a = 2*5 = 10 cm
A = $(10)^{2}$
= 100 $cm^{2}$