Explanation:
1) the 1-st prism is cube. Then its surface area can be calculated as:
A=5*5*6=150 [ft²];
2) A=[Perimeter of triange]*height+2*[Area_of_triangle];
according to the formula above height=3; Perimeter of triangle=9+12+15=36; Area of triangle=12*9*0.5=54;
Finally, A=36*3+2*54=108+108=216 [cm²].