THIS IS MY LAST QUESTION PLEASE HELP!
The figure below shows a circle with two chords JM and KL intersecting at point S.

Grace took the measurements of the line segments and wrote them down as shown.

Segment KS is 1.8 cm, segment SM is 2.5 cm, segment JS is 4.5 cm, and segment SL is 1.2 cm.

Describe the method you use to prove that Grace took incorrect measurements. Use geometric theorems to write a two-column proof.

Question

THIS IS MY LAST QUESTION PLEASE HELP! 
The figure below shows a circle with two chords JM and KL intersecting at point S.



Grace took the measurements of the line segments and wrote them down as shown.

Segment KS is 1.8 cm, segment SM is 2.5 cm, segment JS is 4.5 cm, and segment SL is 1.2 cm.

Describe the method you use to prove that Grace took incorrect measurements. Use geometric theorems to write a two-column proof.

anonymous · Answer

http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/pool_Geom_3641_1008_22/image0024e8db140.jpg

anonymous · Answer

This is what I have so far: Grace took incorrect measurements because when you multiply the segments of a chord they must be equal, which they are not.

anonymous · Answer

Now I need to make a two-column proof

saifoo.khan · Answer

@nbouscal @dpaInc

cwrw238 · Answer

2 column proof? - sorry need heard of it. at least i haven't seen it in a uk geometry book

anonymous · Answer

@nbouscal do you think you can help? or @dpaInc

anonymous · Answer

Two column proofs are a weird pedagogical method used at schools here in the states, generally they make kids hate geometry and proofs, it's a really annoying thing.

anonymous · Answer

@nbouscal do you think you can make the two-column proof?

anonymous · Answer

@nbouscal please!

anonymous · Answer

@dpaInc!!!!

anonymous · Answer

obviously you're using some kind of geometry formula...
what is it?  
state that in your proof... because you already mentioned you know somehow she made incorrect measurement from "multiplying" the segments.... state that...

anonymous · Answer

What do you mean "geometry formula"

anonymous · Answer

well, what do you mean by "multiply the segments of a chord" ???

anonymous · Answer

I used it from this http://openstudy.com/study#/updates/4fc7a1bae4b022f1e12f0efb

anonymous · Answer

But I don't really understand what he meant for the proof

anonymous · Answer

yes.. that is an actual theorem.... look here.. http://www.mathwarehouse.com/geometry/circle/index.php

anonymous · Answer

forget about the proof... just mention that the products have to hold....

anonymous · Answer

The question tells you to make a proof though

anonymous · Answer

yes... i know.... i was talking about the proof of the theorem...

anonymous · Answer

I'm sorry I can't think right now...I've been working on this for the past 3 hours and I've just like given up

anonymous · Answer

ok.... let's try this then..
|dw:1343253797926:dw|
label each of those segments with the measurements Grace made...
then show , by algebra that the products don't hold...