Help+With+Excel

When you know any three points of your parabola, you can use a spreadsheet in Excel to find an equation for your parabola.
 * Help With Using Excel to Find Your Equation: **

Step 1: Enter the three points into the spreadsheet. Here is an example with the points for my sample project: (0, 0), (-2.5, 12) , and (-5, 0) 

Step 2: Highlight the data, click the "Insert" tab. Choose "Scatter" - "Scatter with Smooth Lines and Markers".



Step 3: //Right// click on one of the points on the graph. Choose "Add Trendline..."

Step 4: Choose "Polynomial". Make sure the order is 2 (order actually means degree!).

Step 5: Enter your y-intercept in the "Set Intercept =" box. For example, if your parabola goes through the origin, you would enter "0" in the box.

Step 6: Make sure the box for "Display Equation on chart" is checked. Your screen should look like this before you click "Close":



Now you have your equation!