How do we extrapolate a graph, either on Microsoft word or excel?

In Microsoft Excel, you need to enter your data in
columns, and then click the Insert tab at the top of the page, and then find the Charts
section. Choose either a line chart or a scatter chart, and click on it. This will
insert a chart based on your data into the sheet you are working on. Double check to
make sure all your data points are included. (If not, highlight all the data you want
included in the relevant data column(s) and then repeat the instructions
above.)

Once you see the chart, click on the body of the
chart. Then click the tab at the top that says Layout. In the Analysis section of Layout
there is an option that says Trendlines. Click on it, and at the bottom choose More
Trendline Options. Pick either linear or exponential depending on which seems to fit
your line better (use linear for a straight line, exponential for a curve), and add a
number to the Forecast Forward option. If the extrapolation isn't long enough, go back
and increase the number.