# How do you write 7.4 nm in scientific notation?

$7.4 \cdot {10}^{-} 9$ m
One nano meter is 0.000000001 m or $1 \cdot {10}^{-} 9$ m.
So 7.4 nm is $7.4 \cdot {10}^{-} 9$ m
The following chart from http://imgkid.com/scientific-notation-examples-for-kids.shtml tells you how I went from 0.000000001 m to $1 \cdot {10}^{-} 9$ m :