both are regular pentagons, so each have 5 equal sides
now, the ABCDE one, has sides with length of 6√(5), well the perimeter of any shape, is all its sides or its borders, added up, so, 5 sides, each 6√(5), then the perimeter of ABCDE is 6√(5)+6√(5)+6√(5)+6√(5)+6√(5) or 5[ 6√(5) ]
now to get the area of pentagon QRSTU, we know it has 5 sides, and each side is 8cm in length
thus [tex]\bf \textit{area of a regular polygon}\\\\
A=\cfrac{1}{4}\cdot n\cdot s^2\cdot cot\left( \frac{180}{n} \right)\qquad
\begin{cases}
n=\textit{number of sides}\\
s=\textit{length of one side}\\
\frac{180}{n}=\textit{angle in degrees}\\
----------\\
n=5\\
s=8
\end{cases}
\\\\\\
A=\cfrac{1}{4}\cdot 5\cdot 8^2\cdot cot\left( \frac{180}{5} \right)[/tex]
now, the angle there is in degrees, thus, make sure your calculator is in Degree mode
