To find the ratio of the area of the dilated square to the area of the original square, we first need to calculate each of the areas.
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Area of the original square: The formula for the area \(A\) of a square with side length \(s\) is: \[ A = s^2 \] For the original square with a side length of 5 cm: \[ A_{\text{original}} = 5^2 = 25 , \text{cm}^2 \]
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Dilating the square: The scale factor for the dilation is 4. Therefore, the new side length of the dilated square is: \[ s_{\text{dilated}} = 5 \times 4 = 20 , \text{cm} \]
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Area of the dilated square: Using the same area formula: \[ A_{\text{dilated}} = (s_{\text{dilated}})^2 = 20^2 = 400 , \text{cm}^2 \]
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Finding the ratio of the areas: The ratio of the area of the dilated square to the area of the original square is: \[ \text{Ratio} = \frac{A_{\text{dilated}}}{A_{\text{original}}} = \frac{400}{25} \] Simplifying the ratio: \[ \text{Ratio} = 16 \]
Therefore, the ratio of the area of the dilated square to the area of the original square is \(\boxed{16}\).