A square and a triangle have equal perimeters.  The lengths of the three sides of the triangle are 6.2, 8.3 and 9.5.  The area of the square is
$\text{(A)}\ 24\text{ cm}^2 \qquad \text{(B)}\ 36\text{ cm}^2 \qquad \text{(C)}\ 48\text{ cm}^2 \qquad \text{(D)}\ 64\text{ cm}^2 \qquad \text{(E)}\ 144\text{ cm}^2$
We are given the three side lengths of the triangle, so we can compute the perimeter of the triangle to be $6.2+8.3+9.5=24$.  The square has the same perimeter as the triangle, so its side length is $\frac{24}{4}=6$. Finally, the area of the square is $6^2=36$, which is choice $\boxed{\text{B}}$