Hi Saied,

Yes, you can definitely extrapolate points on a trendline in Excel. Here's how you can do it:

1. First, select the chart that contains the trendline you want to extrapolate.
2. Next, right-click on the trendline and select "Format Trendline" from the drop-down menu.
3. In the "Format Trendline" pane that appears on the right-hand side of the screen, click on the "Options" tab.
4. Under "Forecast," you'll see two input boxes: "Forward" and "Backward."
5. These boxes allow you to specify how far you want to extrapolate the trendline in either direction.
6. In your case, you want to extrapolate the trendline to 24 mm on the x-axis. So, you'll need to enter a value in the "Forward" input box that corresponds to how many units you want to extrapolate beyond the last data point on your chart. For example, if your last data point is at 20 mm, and you want to extrapolate to 24 mm, you would enter "4" in the "Forward" input box.
7. Once you've entered the appropriate values, click "Close" to apply the changes.
8. Now, you should see the trendline extended beyond the last data point on your chart, and you can read off the corresponding y-value at 24 mm on the x-axis.