Given a triangular base pyramid with the following dimensions
![\begin{gathered} For\text{ the lateral sides} \\ h=12m \\ b=8m \\ \text{For the base} \\ h=6.9m \\ b=8m \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/40c3wn7c3vnyqrlv0h5jhfya5c8hw5zihp.png)
To find the total surface area, TSA, of the triangular base pyramid, the formula is
![\text{TSA}=\text{base area}+(1)/(2)(Perimeter* slant\text{ height)}](https://img.qammunity.org/2023/formulas/mathematics/college/r3sn43vdsz1ijhvlt4tncmn0rstmrv0cd9.png)
The base area of the triangular base pyramid is
![\text{Base area}=(1)/(2)bh=(1)/(2)*8*6.9=27.6m^2](https://img.qammunity.org/2023/formulas/mathematics/college/jz4vfqcfkvge2do829osuk2p2y7f9xb59o.png)
For the other part of the total surface area
![\begin{gathered} (1)/(2)(Perimeter* slant\text{ height)}=(1)/(2)((8+8+8)*12) \\ =(1)/(2)(24*12)=(1)/(2)*288=144m^2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/zq201ucnp0dyxpy2qhnpmu2gcbgjdgvz1k.png)
The total surface area of the triangular base pyramid is
![\text{TSA}=\text{base area}+(1)/(2)(Perimeter* slant\text{ height)}=27.6+144=171.6m^2](https://img.qammunity.org/2023/formulas/mathematics/college/q1pgv9j8uuere1ncqy7ju1759lx7l3qacw.png)
Hence, the total surface area of the triangular base pyramid is 171.6m²
To find the lateral area of a triangular base pyramid, the formula is
![\begin{gathered} Lateral\text{ area}=(1)/(2)(Perimeter* slant\text{ height)} \\ =(1)/(2)((8+8+8)*12) \\ (1)/(2)(24*12)=(1)/(2)(24*12)=(1)/(2)(288)=144m^2 \\ Lateral\text{ area}=144m^2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/e76j4smvlm88y2jdltz5hw6s3gga6qfq0m.png)
Hence, the lateral area of the triangular base pyramid is 144m²