Here's the question you clicked on:
webbbiee
In the figure, the horizontal lines are parallel and AB = BC = CD. Find the measure of JM. The diagram is not drawn to scale. A 14 B 21 C 28 D 7
you essentially use the side splitter theorem http://www.cliffsnotes.com/study_guide/Proportional-Parts-of-Triangles.topicArticleId-18851,articleId-18813.html and that allows you to say "If a line is parallel to one side of a triangle and intersects the other two sides, it divides those sides proportionally. " what this means is that you can effectively say that AD/AB = JM/LM (4AB)/AB = JM/7 4 = JM/7 4*7 = JM 28 = JM JM = 28 So JM is 28 units
oh wait, it should be AD/AB = JM/LM (3AB)/AB = JM/7 3 = JM/7 3*7 = JM 21 = JM JM = 21 So JM is 21 units