Question

30 Hand span and footsteps are not reliable units.​

Answer 1

Answer:

The size of the foot and hand varies from person to person. If footsteps or hand span of two persons are used to measure the length respectively, then the two distances may not be equal. Thus, a footstep or hand span are not the constant quantities. Hence, they cannot be used as a standard unit of length

OR

Footstep and handspan both differ in different people.If this would be used as SI unit there would be a lot of confusion because if something is large for someone then it would be small for the other.So meter is used to remove this confusion.

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