The length, l, of a steel rod is 7.3 m, correct to 1 decimal place.
complete the error interval for length l.

  [7.25, 7.35)

Step-by-step explanation:

The least significant digit is in the tenths place. The error can be as much as half of one tenth, or 0.05.

The lower bound is ...

  7.3 - 0.05 = 7.25 . . . . . error subtracted from value

The upper bound is ...

  7.3 + 0.05 = 7.35 . . . . . error added to value

Since 7.35 is rounded up to 7.4, the maximum value of L must be less than that.

  7.25 ≤ L < 7.35 . . . meters

In many cases, the upper bound on L is taken to be exactly 7.35. For all practical purposes it is. If you're asked for upper and lower limits, you'd have to say they are 7.35 and 7.25 m, respectively.

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