# Rebecca has samples of different types of metal. She wants to measure the samples to find out the density of each metal. First, she measures the samples' volumes. Now she needs masses. What tools should Rebecca use to measure her samples' masses?

$\text{Density,}$ $\rho = \text{Mass"/"Volume}$, and thus it has the units of $g \cdot m L$ or $g \cdot c {m}^{-} 3$.