Answer:
129.6 cm²
Step-by-step explanation:
The lateral area (A) is the area of the 4 congruent triangular faces.
A = 4 × [tex]\frac{1}{2}[/tex] bh ( b is the base and h the perpendicular height )
Here b = 8 and h = 8.1 , thus
A = 4 × [tex]\frac{1}{2}[/tex] × 8 × 8.1 = 2 × 8 × 8.1 = 16 × 8.1 = 129.6 cm²
