The PI function returns **3.14159265358979** -- the value of constant pi returned by the function is accurate to 15 digits -- in Microsoft Excel 2013 and Office 365. Use it in your formulas as PI(); the function does not accept any arguments. For example, you can use it to calculate the volume of a sphere. To get the most accurate result, format the cell that contains the formula and change the number of decimal places to **14**.

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Open the spreadsheet you want to edit in Excel 2013 or create a new spreadsheet. Type the radius of the sphere into one of the cells, or locate the cell that contains it.

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Right-click the cell where you want to display the volume of the sphere and choose **Format Cells** from the context menu. The Format Cells dialog displays with the **Number** tab selected by default.

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Select **Number** from the Category section to change the format of the cell and then type **14** into the **Decimal Places** field to use all 14 digits of constant pi in the formula. Click **OK**.

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You can select to use fewer digits, but Excel automatically approximates the value of pi -- for example, it returns **3.142** if you use three decimal places.

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Format the cells further by changing the options on the **Alignment**, **Font**, **Border** and **Fill** tabs.

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Type **=4/3_PI()_Cell^3** into the **Formula** field and replace "*Cell*" with the cell that contains the radius of the sphere. Press **Enter** to calculate the volume of the sphere and display it in the selected cell.

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The **PI()** function returns the value of pi. "/" is the division operator, "*" is the multiplication operator and "^" is the power operator.