Straight Line Chart

[Freshman]

I've created a straight line chart with four data point markers. If I point
my mouse to any data point marker in the chart, the screen tip shows me the
the x-value and y-value of that data point. My question is, if I point to the
any part on the straight line or between two data point marker, is it
possible for me to know the x-value and y-value of that part? Or,
if I know the x-value, how can I know the y-value directly from the straight
line chart.
Please kindly adivse.
Thanks in advance.

 

[BenjieLop]

Your first step is to determine the slope of your line. You can do thi
getting any two of your four data points.

Let's assume that the coordinates of two data points that you picke
are: (x1,y1) and (x2,y2).

Your slope is then = (y2-y1)/(x2-x1)

Since this is a straight line, the slope is constant. Let's assum
further that the coordinates of any point (besides your 4 data points
on the line are (x,y) then apply the slope formula again,

((y2-y1)/(x2-x1))=((y2-y)/(x2-x))

Since you stipulated that you know "x" then the y-value of any point o
the line can be determined by the formula

y = y2 - (x2-x)*((y2-y1)/(x2-x1))

 

[Alex Delamain]

If you add a linear trendline to your chart you can get excel to sho
the equation for the line (by right clicking on the trend line, the
format trendline, options, display equation on chart.

this will give you what you need to calculate any point, in the forma
y=mx+