Answer:
x = 4
Step-by-step explanation:
The volume (V) of the triangular prism is calculated as
V = area of triangular face × length
Area of triangle = [tex]\frac{1}{2}[/tex] bh
b is the base and h the perpendicular height
here b = 9 and h = 12 ← sides at right angles
A = [tex]\frac{1}{2}[/tex] × 9 × 12 = 54 m²
The length of the prism = x and V = 216, hence
54x = 216 ( divide both sides by 54 )
x = 4
