Set up this table, where (x1,y1) is one point, and (x2,y2) is the other:

_|___A_____B_____C__

1|x-value___ser1___ser2

2|___0______0_____0__

3|__x1_____y1________

4|__x2____________y2_

(cells C3 and B4 are blank)

Select the area above, and Insert-Chart

– step 1) pick type Line

– step 2) Series in: Columns

– Series tab: click on the series titled “x-value”, and Remove

– click on Category (X) axis labels: and select A2:A4

– Step 3) Axes tab: make Category (X) Axis: Timescale

– Finish

Now you have to change some settings to get it to look right:

1) Format the x-axis:

– Scale tab: un-check the Value (Y) axis crosses between dates

– Number tab: select Number at left

2) Tools – Options – Chart tab

– Plot empty cells as: Interpolated

Now you should have your two lines going from 0 to the points.

The slope of the lines are: y1/x1, and y2/x2

The third line that would be the average would be from 0 to the x3,y3 coordinates where x3=(x1+x2)/2, and y3=(y1+y2)/2

The slope of this third line is y3 divided by x3, or:

(y1+y2)/2

————

(x1+x2)/2

I hope this gets you what you need. If you need more info, either add more detail or e-mail.

Cheers.

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