Melani C.

asked • 06/23/15

which length measurement is the most precise ?

a. 24.36 centimeters
b. 18.5 centimeters
c. 37 centimeters
d. 50 centimeters

1 Expert Answer

By:

Kehley D. answered • 06/23/15

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David W.

Perhaps 50 should be written as 5.0x101.  Each digit (even 0) indicates an expression of precision.
 
Fortunately all the choices are expressed in centimeters.  Had one of them been in units of meters, it would be necessary to first convert it into scientific notation in units of centimeters (to match the others).
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06/23/15

Kehley D.

David,
I made a judgment call based on the trend of the other numbers to say 50 was only one sigfig, but you're right that it could be two. Thankfully, either way it is beaten out by 24.36cm.
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06/23/15

Harvey F.

50 is considered to have only 1 sigfig while 50. with the decimal expressed denotes 2 sigfigs, so 50 is 5x101 in scientific notation.
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06/23/15

Harvey F.

Precision involves the closeness of several measurements, so a single measurement does not indicate precision. The stated problem is actually seeking the best "measurement discrimination".
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06/23/15

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