It's under Tools>Analyze>Measuring Tool
The "Analyze" panel may not be available by default, you can show it via View>Tools>Analyze
"oh there you are peter" Is there a way to change the scale ratio in the Distance Tool. when I use to use version 7 Pro It was right there. But that was a while back.
With the measuring tool active, right-click anywhere on the document and you should see a menu. Here you can set the scale.