Step-by-step explanation:
Surface area = area of base + 4[tex] \timea[/tex] area of one triangle.
[tex] \therefore \: surface \: area \\ = ( {11})^{2} + 4 \times \frac{1}{2} \times 11 \times 16 \\ \\ = 121 + 4 \times 11 \times 8 \\ \\ = 121 + 352 \\ \\ = 473 \: {in}^{2} \\ \\ \red { \boxed{\therefore \: surface \: area =473 \: {in}^{2} }}[/tex]
