# What is the SI base unit for length?

$\text{The metre...........}$
And $1 \cdot m m \equiv {10}^{-} 3 \cdot m$; and $1 \cdot c m \equiv {10}^{-} 2 \cdot m$..........
Most of the time chemists use $\text{Angstroms} = 1 \times {10}^{-} 10 \cdot m$, because typically bond lengths are $1 - 2$ $\text{Angstroms}$ long.