Solution
Notice that we have two solid shapes and we want to find the surface area of the composite.
We have a triangular prism on a cuboid.
Note: Formula For Finding the Surface Area Of A Cuboid
[tex]Surface\text{ }Area=2(lw+lh+wh)[/tex]
From the question, we have that
[tex]\begin{gathered} Length(l)=12cm \\ Width(w)=4cm \\ Height(h)=14cm \end{gathered}[/tex]
The area will be
[tex]\begin{gathered} Surface\text{ A}rea=2(lw+lh+wh) \\ \\ Surface\text{ A}rea=2(12(4)+12(14)+4(14)) \\ \\ Surface\text{ A}rea=2(48+168+56) \\ \\ Surface\text{ A}rea=2(272) \\ \\ Surface\text{ A}rea=544cm^2 \end{gathered}[/tex]
Now, we find the Area of the Triangular Prism
Note: Formula To Use
From the question, we have
[tex]\begin{gathered} b=4cm \\ h=2\sqrt{3}\text{ \lparen since the triangle is an equilateral triangle\rparen} \\ L=12cm \\ S_1=S_2=S_3=4cm \end{gathered}[/tex]
Substituting we have
[tex]\begin{gathered} Surface\text{ }Area=bh+L(S_1+S_2+S_3) \\ \\ Surface\text{ }Area=4(2\sqrt{3})+12(4+4+4) \\ \\ Surface\text{ }Area=(8\sqrt{3}+144)cm^2 \end{gathered}[/tex]
Therefore, the total surface area of the composite is
[tex]\begin{gathered} Surface\text{ }Area=544+8\sqrt{3}+144 \\ \\ Surface\text{ }Area=(688+8\sqrt{3})cm^2 \\ or\text{ if we want to write the answer in decimal point, we have} \\ Surface\text{ }Area=701.8564065cm^2 \end{gathered}[/tex]
