Answer :
Explanation
To find the surface area of the pyramid, we will find the area of the square base and sum it to the areas of the triangular surfaces.
[tex]Area\text{ of S.B =}edge\text{ }lenght^2=10^2=100units^2[/tex]The area of one triangular surface is
[tex]Area\text{ of T.F=}\frac{1}{2}\times edge\text{ }length\times slant\text{ }height=\frac{1}{2}\times10\times12=60cm^2[/tex]Since the triangular prism has four triangular surfaces, therefore the sum of the area of the triangular faces is
[tex]4\times Area\text{ of T.F}=4\times60=240units^2[/tex]Therefore, the surface area of the triangular prism becomes
[tex]\begin{gathered} S.A=4\times Area\text{ of T.F}+Area\text{ of S.B} \\ =240+100=340units^2 \end{gathered}[/tex]Answer: Option A