See above screen shot. On the Ribbons Chart Layout tab go to the Analysis group and choose LinesDrop Lines to add lines from your data points to the X-axis. In the Category list click Number and then change the Decimal places setting to 30 or less.
Here were going to cover how to add a trendline in Excel.
Select the Numbertab and then select Numberin the Categorylist. Youll see something like whats in the red box below appear on your chart. If you want to apply a trendline to only one of the data series right-click on the desired item. The Format Trendline pane opens so you can select the trendline you want.