Answer:
249.6 square units
Step-by-step explanation:
The surface area of a tetrahedron consists of 4 times the same areas. So we just need to get the area a of the triangle with the given height h = 10.4 and base length b = 12 which is [tex]a = \frac{b \cdot h}{2} = 62.4[/tex]. Multiply with 4 to get the whole thing.
