Finding values on Y axis for two intersecting lines

[tellganesh]

Please take a look at the graph,

<table style="width:194px;"><tr><td align="center" style="height:194px;background:url(https://picasaweb.google.com/s/c/transparent_album_background.gif) no-repeat left"><a href="https://picasaweb.google.com/110513450217860738841/October52012?authuser=0&feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-M6_VJjN5U64/UG57bH9FCrE/AAAAAAAAAIM/iwK7f9sndqY/s160-c/October52012.jpg" width="160" height="160" style="margin:1px 0 0 4px;"></a></td></tr><tr><td style="text-align:center;font-family:arial,sans-serif;font-size:11px"><a href="https://picasaweb.google.com/110513450217860738841/October52012?authuser=0&feat=embedwebsite" style="color:#4D4D4D;font-weight:bold;text-decoration:none;">October 5, 2012</a></td></tr></table>

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There are two lines intersecting as you can see. What I would want is that to get the corresponding value on Y axis automatically for the intersecting points. I want to know what command to use to accomplish this. For this case its roughly 25% on Y axis and so I want excel to display the 25% in a specific cell. I would greatly appreciate if someone has any ideas.

 

[pgc01]

Hi

2 steps

1 - find the equations of the lines
2 - caclulate their intersection

For step 1,
- one of the lines is a vertical line, so no problem here
- for the other you either have the equation or must use an approximate equation, for ex. using a trendline

For step 2
Either the equations are such that you can derive a closed solution or you can use some numerical method to find the intersection, for ex. using goal seek or writing a udf to do it.

 

[tellganesh]

Dear PGC,

Thanks for your reply,

Can we do anything from the source values for the graphical lines. What i am trying to say is that, these two lines are created from two set of data. The intersection point on the graph should be the value where they are same. Can we play around it?

For the step 1 you discussed, these graphs will dynamically change for different values and so the trendline that we use should be changed now and then which is not possible. I am not sure to write a UDF? can you show me one?

Thanks,
Ganesh