Answer:
Area of triangular Base is 8 feet² & Edge length is 4 feet.
Step-by-step explanation:
Given: Volume of Rectangular prism = 72 feet³
Height of prism = 9 feet
triangle of base is an isosceles right angled triangle.
To find: Area of Triangular Base & Edge of triangle
we know that,
Volume of Prism = Area of Base × Height
⇒ Area of Triangular Base × 9 = 72
Area of Triangular Base = 
Area of Triangular Base = 8 feet²
Triangular Base is an isosceles right angled triangle .i.e., perpendicular legs are equal in length say x.




x = 4
Length of Edge = 4 feet
Therefore, Area of triangular Base is 8 feet² & Edge length is 4 feet.