<u>Answer:</u>
Lengths of the sides (there are 3 sides in an equilateral triangle) of the base of prism is <u>5.72cm </u>each.
<u>Step-by-step explanation:</u>
As the base of triangular prism is equilateral:
∴ Area of base = (√ 3 / 4)× (side)²
According to question:
height of prism = height (side) of base
Volume of prism = 81 cm³,
∴ Volume of prism = Area of base x height
⇒ 81 cm³ = (√ 3 / 4)× (side)² × height ∵ side = height
⇒ 81 cm³ = (√ 3 / 4)× (side)³
⇒ 81 × (4/√3) cm³ = side³
⇒ ∛(81 × (4/√3) cm = side
⇒ side = <u>5.72cm</u>