# Question #a6453

Jul 25, 2017

One significant figure.

#### Explanation:

You're dealing with multiplication and division, so you should round the answer to the number of significant figures in the least precise measurement.

In other words, your answer cannot be more precise than the least precise measurement you used when calculating the answer.

In this case, you have

• $1.9 \to$ two sig figs
• $\textcolor{b l u e}{2} \textcolor{w h i t e}{1.} \to$ one sig fig
• $\textcolor{b l u e}{4} \textcolor{w h i t e}{1.} \to$ one sig fig

So, start by doing the division

$1.9 \div \textcolor{b l u e}{2} = 0.95$

This answer should be rounded to one significant figure, but you should keep at least one extra significant figure as a guard digit.

Next, do

$0.95 \times \textcolor{b l u e}{4} = 3.8$

At this point, you should round the final answer to $1$ significant figure, the number of sig figs you have for your least precise measurements, i.e. $\textcolor{b l u e}{2}$ and $\textcolor{b l u e}{4}$.

Since

$3.8 = 4 \to$ rounded to one significant figure

$1.9 \div 2 \times 4 = 4$