To find out how much space Robert will have left after placing the 10 squares, we first need to calculate the total area occupied by the squares.
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Calculate the area of one square: \[ s = 7 \text{ inches} \] Area of one square: \[ s^2 = 7^2 = 49 \text{ square inches} \]
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Calculate the total area of 10 squares: \[ 10s^2 = 10 \times 49 = 490 \text{ square inches} \]
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Calculate the remaining area on the poster: \[ 720 - 10s^2 = 720 - 490 = 230 \text{ square inches} \]
Therefore, the space Robert will have left for his presentation is 230 square inches.
The correct response is: 230 square inches.