Exercise 6 Page 390

To find $XZ,$ we should use the Segment Addition Postulate. This postulate tells us that, if we have a point between two points, we can add the lengths of the two smaller segments to find the length of the longer segment. In our case, $Y$ is between $X$ and $Z,$ so we can get the length $XZ$ by adding $XY$ and $YZ.$ From the diagram, we know that the length $XY$ is $23$ and the length $YZ$ is $50.$ Now, we can use this to calculate $XZ.$ The length $XZ$ is $73.$