# The mass of a proton is 1.67272 x 10^-27 kg. What is its mass in ng?

$1 \cdot n g$ $=$ ${10}^{-} 9 g$, and $1 \cdot k g$ $=$ ${10}^{3} \cdot g$
Well $1 \cdot n g$ $=$ ${10}^{-} 9 g$, and $1 \cdot k g$ $=$ ${10}^{3} \cdot g$
Thus $1 \cdot n g$ $=$ ${10}^{-} 12 \cdot k g$
So $1.67272 \times {10}^{-} 27 \cdot k g$ $=$ $\frac{1.67272 \times {10}^{-} 27 \cdot k g}{{10}^{-} 12 \cdot k g \cdot n {g}^{-} 1}$ $=$ $1.67272 \times {10}^{-} 15 \cdot n g$