The footstep as a measure of length is unreliable measure of length because different people have different foot sizes.
So the device measurement is not accurate due to the apparatus. These errors are categorized into three type's namely absolute error, relative error, and percentage error. The absolute error can be defined as the variation between the values of actual and measured.
With the development in the field of science and technology, the need for a commonly accepted system of units is realized all over the world particularly to exchange scientific and technical information. SI unit enables us to calculate easily by being a constant term of measurement throughout the world
