How can the height of a person who is six feet tall be expressed (approximately) in nanometers?

Convert 6 feet to metres using 1 ft = 0.3048 m: 6 × 0.3048 = 1.8288 m. Convert metres to nanometres using 1 nm = 1.0×10^-9 m, so 1 m = 10^9 nm [1]. Therefore 1.8288 m = 1.8288 × 10^9 nm ≈ 1.83 × 10^9 nm. Match this to the options’ formats: 183 × 10^7 nm = 183 × 10^7 = 1.83 × 10^9 nm, which agrees with the calculated value (rounded). Hence option 3 is the best approximate representation of a six‑foot person's height in nanometres.

Sources

1. [1] https://www.ldeo.columbia.edu/~martins/hydro/conversion.htm