Appearances may be deceiving. Although perhaps you think you've identified the killer, investigators use an additional technique to match up hair samples.

Next, you'll use WebImage to measure the diameter of each hair and then the diameter of each medulla--if there is one. Then you'll find the ratio, or relationship, between the two by dividing the diameter of the hair by the diameter of the medulla.

First, measure the hair in CrimeSceneHair.gif. Make sure that Line is selected in the pull-down menu below the Zoom Out button. Then click the Draw button.

Use your mouse to draw a line across the hair shaft. Then click Measure.

The answer should appear in the Measure Results box.