Final answer:
To divide the value in cell B5 by the value in cell B15 with an absolute cell reference, use the formula '=B5/$B$15' in cell C5. This keeps the reference to cell B15 constant when the formula is copied.
Step-by-step explanation:
To enter a formula in cell C5 that divides the value in cell B5 by the value in cell B15 using an absolute cell reference to cell B15, you should write the following in cell C5: =B5/$B$15
This formula uses absolute cell referencing for cell B15. This means that if you copy the formula to another cell, the reference to cell B15 will stay constant, which is indicated by the dollar signs before the column letter and row number. Using an absolute cell reference is necessary when you want to maintain a reference to the same cell even when the formula is applied to different locations in your spreadsheet.