Answer:
- minimum: 6.75 km²
- maximum: 13.75 km²
Explanation:
Such questions generally arise in the context of measurement precision and/or accuracy. Apparently, we're to assume that these dimensions could be arrived at by rounding to the nearest km. In that case, they can be taken to have a possible error of ±0.5 km.
The minimum possible area is the product of the minimum possible dimensions: 1.5 km by 4.5 km = 6.75 km².
The maximum possible area is the product of the maximum possible dimensions: 2.5 km by 5.5 km = 13.75 km².
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Comment on combining measurement values
You will note that the nominal area is 2 km by 5 km = 10 km², and that the middle value between the minimum and maximum is slightly more than this, at 10.25 km².
It is typically the case that when measurements are combined by operations other than addition and subtraction, the nominal result is different from the middle result in the range of possibilities.