INFORMATION:
We have the next figure
And we must find its surface area
STEP BY STEP EXPLANATION:
To find the surface area we need to all the areas of each face of the figure.
We know that the area of the pentagonal face is 15.5 km^2
Now, we must find the area of the rectangular faces knowing that the base is 3km and the height is 18km

Now, we have 2 pentagonal faces and 5 rectangular faces
Then, we must add all areas to find the surface area of the figure

Finally, the surface area of the figure is 301km^2
ANSWER:
the surface area of the figure is 301km^2