Answer:
~27.764982043070833894247682407876
Explanation:
First, we can add 8+5.5+8 because of the two sides which are 8 and one that is 5.5. That is 21.5.
Then, we must find the diagonal edge. To do that, we can use the pythagorean theorem. It makes a triangle, so given that a^2+b^2=c^c, we can say that 3^2+5.5^2=c^c. Using a calculator, we can find the square root of 39.25, then add it to 21.5.