How to Use the Tangent Function in Excel

1. Open up the Excel worksheet where you want to use Excel's tangent function.
2. Select the cell where you want to determine the tangent of an angle.
3. Enter in the following formula:=TAN(X)where 'X' equals the angle you want the tangent for, in radians. If 'X' is listed in another cell, you can instead use a cell reference, like A1 or B12 for 'X.' If your angle information is in degrees, use this formula instead:=TAN(RADIANS(X))as the RADIANS formula will convert the angle to radians.