Answer:20.7 units²
Step-by-step explanation: volume of a rectangular prism is L×W×H
therefore 82.8=L×W×the height which is 4 units so if u do 4×L×W you get 4LW which is the volume
(4LW=82.8) now divide 82.8 by 4LW to get the value of LW. The value of LW is an area of one of the bases because area is L×W which is basically LW
hope you understand all the best