Diagram shows the first four squares from a series of squares.The side of these squares decreases in a geometric progression.The side of the first square is $\displaystyle h$ cm and the side of the subsequent square is $\displaystyle \frac{3}{4} h$. cm

a)if the sum of the perimeters of the first five squares is $\displaystyle \frac{781}{4}cm$. find the value of $\displaystyle h$.

b)Hence,find the area of the $\displaystyle 5^{th}$ square.