Answer
An order of magnitude estimate of a variable whose precise value is unknown is an estimate rounded to the nearest power of ten. Hence, the accuracy of the answer is expected to be within a factor of 10 of the exact answer. For example, if a length result of $10^{5}$ km were obtained, it would be expected that the exact answer was somewhere between $1\times10^{5}$ and $10\times10^{5}$ .
Work Step by Step
An order of magnitude estimate of a variable whose precise value is unknown is an estimate rounded to the nearest power of ten. Hence, the accuracy of the answer is expected to be within a factor of 10 of the exact answer. For example, if a length result of $10^{5}$ km were obtained, it would be expected that the exact answer was somewhere between $1\times10^{5}$ and $10\times10^{5}$ .