The picture in the attached figure
we know that
surface area=2*area of the base+perimeter*height
area of the base=area of the triangle
area of the base=3*4/2----> 6 cm²
perimeter of the base=perimeter of triangle
perimeter=3+4+5----> 12 cm
height=x cm
surface area=2*6+12*x
surface area=204 cm²
12+12*x=204
12*x=204-12
12*x=192
x=192/12
x=16 cm
the answer is
16 cm
we know that
surface area=2*area of the base+perimeter*height
area of the base=area of the triangle
area of the base=3*4/2----> 6 cm²
perimeter of the base=perimeter of triangle
perimeter=3+4+5----> 12 cm
height=x cm
surface area=2*6+12*x
surface area=204 cm²
12+12*x=204
12*x=204-12
12*x=192
x=192/12
x=16 cm
the answer is
16 cm