EDGE Math 8

Example

Points R, O, and S lie on a line with the coordinates 5, 10, and –3, respectively. Which point lies between the other two?

Solution

Using the definition of the term "between," you will get

\begin{array}{l} R O = O R = | 10 - 5 | = 5, \\ R S = S R = | 5 - (- 3) | = 8, \\ S O = O S = | 10 - (- 3) | = 13. \end{array}

You can see that $R S + R O = S O .$ Thus, point R lies between points S and O.

You can check if this is correct using a number line, as shown below.