Let's do all work in feet.
The rectangle is 8 ft long.
We convert inches to feet.
It is 4 inches high. 4 in/(12 in/ft) = 1/3 ft
The price of concrete is $98/yd^3
He spends $58.07 in concrete, so he buys $58.07/($98/yd^3) = 0.59255 yd^3
We now know the number of cubic yards he needs, so now we convert to cubic feet.
1 yd^3 = (3 ft)^3 = 27 ft^3
0.59255 yd^3 * (27 ft^3)/(1 yd^3) = 16 ft^3
He needs 16 ft^3.
The rectangular portion of the driveway is a rectangular prism. It has a volume of 16 ft^3, a length of 8 ft, and a height of 1/3 ft.
volume = length * width * height.
16 ft^3 = 8 ft * w * 1/3 ft
16 ft^3 = 8/3 ft^2 * w
w = 3/8 * 16 ft
w = 6 ft
The width is 6 ft.
