The surface area of a triangular prism can be calculated using the formula:
\[ \text{S.A.} = (B) + (S_1 + S_2 + S_3) \]
Here:
- \( B \) represents the area of the triangular base of the prism.
- \( S_1 \), \( S_2 \), and \( S_3 \) are the areas of the three rectangular lateral faces (sides) of the prism.
So, when filling in the blanks, it would be:
The surface area of a triangular prism is S.A. = (B) + (S1 + S2 + S3).