Question

what is the length of $overline{lm}$?

Explanation:

Step1: Identify coordinates

The coordinate of point $L$ is $- 60$ and of point $M$ is $20$.

Step2: Use distance formula

The distance between two points on a number - line is $d=\vert x_2 - x_1\vert$. Here, $x_1=-60$ and $x_2 = 20$. So, $d=\vert20-(-60)\vert$.

Step3: Simplify the expression

$\vert20 + 60\vert=\vert80\vert = 80$.

Answer:

$80$