Final answer:
To extend the formula in cell I6 down the data range, select the cell, use the Fill Handle, and drag it down to copy the formula to each cell in the range. Excel adjusts the cell references automatically unless the formula uses absolute references.
Step-by-step explanation:
To extend the formula in cell I6 to the bottom of the provided data range in the Mileage Log worksheet using the Fill Down feature, you need to follow these steps:
Select cell I6 which contains the formula you wish to extend.
Move your cursor to the bottom-right corner of the cell until it turns into a small black "plus" sign or Fill Handle.
Click and drag the Fill Handle down to the last cell of the data range where you want the formula to be copied.
Release the mouse button, and the formula will be copied, or filled down, into all the selected cells.
As you drag down, Excel will automatically adjust the cell references in the formula relative to each row.
This is assuming the formula is designed to adjust relatively and not using absolute references (like $I$6).
If you have a large data range, you can also double-click on the Fill Handle instead of dragging, and Excel will automatically fill the formula down to the end of the contiguous range that has data in the adjacent column.