Answer:
6 feet by 5 feet by 4 feet
7 feet by 6 feet by 4 feet
Explanation:
The surface are of rectangular prism = 140 ft²
Surface area of rectangular prism is given by :
A = 2(lw + lh + wh)
Using trial by error method :
6 feet by 2 feet by 3 feet
A = 2(6*2 + 6*3 + 2*3) = 72ft²
6 feet by 5 feet by 4 feet
A = 2(6*5 + 6*4 + 5*4) = 148 ft²
7 feet by 6 feet by 4 feet
A = 2(7*6 + 7*4 + 6*4) = 188ft²
8 feet by 4 feet by 3 feet
A = 2(8*4 + 8*3 + 4*3) = 136ft²