A student recorded the length of a piece of wire measured with the meter scale as 98.6cm. What is the relative error in the measurement?

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Depends on the instrument you are measuring with. But as a general rule:
The degree of accuracy is half a unit each side of the unit of measure.

A meter scale could be a stick like a yard stick or a steel bar. You need to give more specifics or just go with ma0641 because its should get you past this quiz.

14 mm is not much in a meter measurement