Answer:
4.63 cubic yard.
Step-by-step explanation:
Given,
The length of sidewalk, l = 100 feet,
Width, w = 5 feet,
Depth, h = 3 inches = 0.25 feet,
Thus, the volume of the concrete needed for making the sidewalk,
= 125 cubic feet,
∵ 1 cubic yard = 27 cubic feet,
⇒ 1 cubic feet = cubic yard,
Thus, the quantity of concrete needed = ≈ 4.63 cubic yard.