To determine the amount of wallpaper Katerina needs to purchase, we first need to calculate the total area of the wall and then subtract the area of the windows.
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Calculate the area of the wall: \[ \text{Area of the wall} = \text{height} \times \text{length} = 10 , \text{ft} \times 18 , \text{ft} = 180 , \text{ft}^2 \]
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Calculate the area of one window: \[ \text{Area of one window} = \text{height} \times \text{length} = 6 , \text{ft} \times 4 , \text{ft} = 24 , \text{ft}^2 \]
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Calculate the area of both windows: \[ \text{Area of both windows} = 2 \times 24 , \text{ft}^2 = 48 , \text{ft}^2 \]
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Subtract the area of the windows from the area of the wall to find the area that needs to be covered with wallpaper: \[ \text{Area to be covered} = \text{Area of the wall} - \text{Area of both windows} = 180 , \text{ft}^2 - 48 , \text{ft}^2 = 132 , \text{ft}^2 \]
Thus, Katerina should purchase 132 ft² of wallpaper.
The correct response is 132 ft².