Answer:
D. 283.2 units²
Explanation:
Surface area of the triangular prism = 2×Base Area + Perimeter of triangular base×height of prism
Base Area = ½*bh
b = 6 km
h = 5.2 km
Base area = ½*6*5.2 = 15.6 km²
Perimeter of triangular base = 6+6+6 = 18 km
Height of prism = 14 km
Plug in the values into the equation
Surface area of triangular prism = 2×15.6 + 18×14
= 31.2 + 252
= 283.2 km²