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

Question

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

anonymous · Answer

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jim_thompson5910 · Answer

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

jim_thompson5910 · Answer

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