how can i determine the area under a graph ( distance vrs height)

[Surfet]

Hi

i have a graph of distance vs heigh which i would like to calculate the
area underneather the curve to give me square meters. Can this be done in
excel and how would i do it?

thanks

 

[joel]

Excel is not the best tool for getting area under the curve. I on'
know what the resolution of your data is or if the line is straight o
curved.

the simple solution is to use you source data for the chart to caculat
the results. the easiest way is with rectangular approximation

X y
1 5
4 3
6 4
7 6
9 7
10 5
11 3
8 17 2


The area between the 1st and 2nd point is 5/(4 - 1) = 2/3

The solution would be to add up all these values to get the area unde
the curve.

the 2nd method is triangular approximation which gives better results.
the area under the curve would be divided into 2 pieces. the rectagula
area and the triangular area

the rectangular area would be the height of the smallest Y valu time
the X value which for the 1st two points is 3 * 3. the triangular are
is the different of the Y heights times the X valu divided by 2 (are
triangle is = 1/2 * l * w). In your case this piece is abs(3-5)/(4-1).


another method for curved lines is to add a trendline to your graph b
right clicking the graph and choose add trendline and in the trend lin
option choose display formula. then use the formula to calculate th
area using the same method I describe above for either rectalgular o
triangular approximation.


If you do a search on the web for Rectangular approximation o
Triangular approximation you will get a better description of what I'
doing

 

[Bernard Liengme]

See
http://people.stfx.ca/bliengme/ExcelTips/AreaUnderCurve.htm
best wishes

 

[tuca via OfficeKB.com]

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