Question

find measurement for pr.

Explanation:

Step1: Identify coordinates

Let's assume the coordinate of point $P$ is $1$ (not shown in the problem - perhaps a mis - label, but we'll work with the given options and the number line concept). The coordinate of point $R$ is $4$.

Step2: Use distance formula on number line

The distance between two points $x_1$ and $x_2$ on a number line is $d=\vert x_2 - x_1\vert$. Here, if $x_1 = 1$ and $x_2=4$, then $d=\vert4 - 1\vert$.
$d=\vert4 - 1\vert=3$

Answer:

3