#### Answer

$$3.2$$

#### Work Step by Step

The distance $d$ between the two points $(x_{1},y_{1})$ and $(x_{2},y_{2})$ is given by
$$d=\sqrt {(x_{2}-x_{1})^{2} + (y_{2}-y_{1})^{2}}.$$
Substitute $x_{1}=2$, $y_{1}=1$, $x_{2}=3$ and $y_{2}=4$ and round to the nearest tenth.
$$d=\sqrt {(3-2)^{2}+(4-1)^{2}}=\sqrt {1+9}=\sqrt{10}=3.2$$