eHow - Educationhttp://www.ehow.com/guide_19-http://www.ehow.com/guide_19-education.html.htmlwww.ehow.comHow to Use a Rulerhttp://www.ehow.com/how_4756722_use-ruler.htmlA ruler can be used to draw straight lines and to take measurements of lines. Take measurements in inches or centimeters by using a ruler with help from a tutor and teacher in this free video on educational tools and teaching. Published on 2/4/2009