The lateral area is 235.8 km. The surface area is 329.4 km
LA = 1/2 * p * l : where p = perimeter and l = slant height
Compute p first = base x # of sides
p = 6 x 6
p = 36
LA = 1/2 x 36 x 13.1
LA = 235.8 km
SA = 1/2 a p + LA : where a = apothem and p = perimeter
SA = (1/2 x 5.2 x 36) + 235.8
SA = 93.6 + 235.8
SA = 329.4 km