ExcelBanter - How to use goal seek

Can u pls tell me how to use Goal Seek function in excel sheet.

Goal seek is used when:
- a worksheet is set up to calculate a result, and
- the "result" depends on a constant value in a cell, and
- you know what "result" you want to get, and
- you want to find out what "constant value" gets that result.

The steps a

1. Select the cell where the result is calculated.

2. Use
Tools Goal seek
The selected cell will be shown in the "Set cell" box.

3. In the "To value" box, put the result you want to get.

4. In the "by changing cell" box identify where the "constant value" is
(the desired value will be stored there by Goal Seek).

5. Click OK.

6. The result appears in the dialog box. If you approve, click OK to put
it in the spreadsheet.

Example: if there weren't a formula to calculate square roots we could
use Goal Seek:

A1 is where the square root will be.
A2 holds the value you want the square root of.
A3 has the formula =A1*A1-A2

In the goal seek dialog box,
Set cell A3
To value 0
By changing cell A1

Goal Seek gets an approximate answer by doing a repetitive calculation
behind the scenes.

Not all calculations set up this way have a valid answer. An example is
the square root of -1. In such cases, Goal Seek tries for a while and
then gives up. So check the outcome. In the square-root example, I'd put
something like this in A4:
=IF(ABS(A3)0.01,"ERROR","")

Also, a problem can have more than one answer. The square root of 25 can
be +5 or -5; which you get depends on what starting point is in A1.