Question

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

Explanation:

Step1: Identify coordinates of E and F

Let's assume E is at (-3, 5) and F is at (3, 5) (by observing the grid - the y - coordinates are the same).

Step2: Use distance formula for points with same y - coordinate

The distance $d$ between two points $(x_1,y)$ and $(x_2,y)$ is $d=\vert x_2 - x_1\vert$. Here $x_1=-3$, $x_2 = 3$, so $d=\vert3-(-3)\vert=\vert3 + 3\vert=6$.

Answer:

6 units