Question

what is the coordinate of the midpoint of $overline{cd}$? write your answer as an integer or a decimal, or mixed number in simplest form.

Explanation:

Step1: Identify the coordinates

The coordinate of point $C$ is $- 60$ and the coordinate of point $D$ is $20$.

Step2: Apply mid - point formula

The mid - point formula for two points $x_1$ and $x_2$ on a number line is $\frac{x_1 + x_2}{2}$. Here $x_1=-60$ and $x_2 = 20$, so we calculate $\frac{-60 + 20}{2}$.
First, calculate the sum in the numerator: $-60+20=-40$.
Then, divide by 2: $\frac{-40}{2}=-20$.

Answer:

$-20$