It is a composite solid, the surface area wil be given by the surface area of the rectangular prism and the surface area of the triangular prism, therefore:
The surface area of the rectangular prism is:
[tex]SA_{rectangular}=2(12\cdot3+4\cdot3+12\cdot\frac{4}{2})=2(72)=144cm^2[/tex][tex]SA_{triangular}=5\cdot12+5\cdot4+13\cdot4=132cm^2[/tex]
Therefore, the surface area of the composite figure is:
[tex]SA=144cm^2+132cm^2=276cm^2[/tex]
Answer:
276 cm²
