Answer:
1658 m^2.
Explanation:
This equals the surface area of the exposed sides of large rectangular prism + surface area of the exposed sides of the triangular prism
= 2 * 25*10 + 2 * 15*25 + 10 * 15
+ 2 * 1/2 * 6 * 8 + 8 * 15 + 6 * 15
= 1400 + 258
= 1658 m^2.