To find the volume of the two-winged building, we first need to calculate the volume of each rectangular prism separately and then add them together.
Volume of the horizontal rectangular prism:
Volume = length x width x height
Volume = 30m x 6m x 9m
Volume = 1620 cubic meters
Volume of the smaller perpendicular rectangular prism:
Volume = length x width x height
Volume = 21m x 6m x 9m
Volume = 1134 cubic meters
Total volume of the corner store:
Total volume = Volume of horizontal prism + Volume of smaller prism
Total volume = 1620 cubic meters + 1134 cubic meters
Total volume = 2754 cubic meters
Therefore, the total volume of the corner store is 2754 cubic meters.