The perimeter of a square is $36 \mathrm{~cm}$. The area of the square, in $\mathrm{cm}^{2}$, is
(A) 24
(B) 81
(C) 36
(D) 1296
(E) 324
Since the four sides of a square are equal in length and the perimeter is $36 \mathrm{~cm}$, then each side has length $\frac{36}{4}=9 \mathrm{~cm}$.

The area of the square is the product of the length and width, which are each equal to $9 \mathrm{~cm}$. Therefore, the area of the square, in $\mathrm{cm}^{2}$, is $9 \times 9=81$.

ANSwER: (B)