Answer:
The measurement for the length of the walls.
Explanation:
Given
per gallon
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Required
The additional information needed to solve the question
First, we need to calculate the area of the walls of the bedroom.
The height of the ceilings represents the length/width of the walls; so, we need the width of each side of the bedroom.
Since the width is not given, then we can conclude that the additional information needed is the length/width of the walls.