52:4 is the scale, but they probably want it in the simplest form so 13:3
52 is 13 times bigger than 4, so the scale fatore is 13 or 1:13 as a ratio (although im not sure when the length of 53 is being measured in)
The scale factor is found by comparing the given lengths, resulting in a ratio of 13:1. This means that 1 inch corresponds to 13 units in the scaled representation. Therefore, the scale factor simplifies to 13:1.
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