The pentagon's area is the sum of the 5 triangles that comprise it. This is
[tex]5( \frac{1}{2}bh) \times 2=5(9)(6.2)= 279[/tex]
where the factor of 2 accounts for the top and bottom. The walls have an area of 5 rectangles
[tex]5(bh)=5(9)(6)=270 \\ \\ 279+270=549km^2[/tex]
