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, Recommended Settings: Set General to R1C1 Off and Show the 10 Most Recent Documents; Edit - set all the Top options to checked except Automatically Convert Date System. Display number of decimal places = blank (for integers preferred), Preserve display of dates and set 30 for 21st century cutoff; View - show Formula Bar and Status Bar, hover for comments and all of Objects, Show gridlines and all boxes below that auto or checked; Chart - show chart names and data markers on hover. Leave rest unchecked for now; Calculation -- Automatically and calc before save, max change .000,000,000,000,01 w/o commas if you do goal-seeking a lot and save external link values and use 1904 system; Error checking - check all; Save - save preview picture with new files and Save Autorecover after 5 minutes; Ribbon -- all checked except Hide group titles and Developer.
 The steps of Neutral Operations for Addition vs. Multiplication are: a+b = ab; a+b-b = ab-b; a = b(a-1); a/(a-1) = b and b has been isolated and defined in terms of a and 1 but a may not = 1 lest division by 0 result in the denominator. Also, it's possible to start out by subtracting a from both sides instead of b, and because both addition and multiplication are commutative, it is also true that b/(b-1) = a. It's symmetrical, which is a hot property in math these days. For more on Neutral Operations, google NeuOps-Graphs01.
 A1: a.r (for the radius of a); B1: b.r; C1: c: (the sum of a+b); D1: a; E1: b; F1 c (the product of a*b); G1: Goal; H1 0. Format Cells Alignment Horizontal Centered and Font Underlined,

, B2: a guess at the answer to the equation =(PI()*B2^2)/((PI()*B2^2)-1) -- D2 should = 9, so 9/π = 3 roughly and 3/(3-1) =1.5, so the square root of that is about 1.22, so enter that as a preliminary guesstimate at the value of b.r  -- or just enter 1. This is the cell that will contain the goal seeking answer and it must start with a preliminary guess.
 The open parentheses for pi() are correct. This statement then is similar to stating that a = b/(b-1) where b=πr^2 and r of b.r resides in cell B2.
 This is what we want a to equal, as the first part of c. In cell G2 enter 9 as this is our Goal Value. In cell H2, subtract F2 from G2, i.e. subtract the goal seeking result from the goal and we want the difference to equal 0.
 In the Excel menu under Preferences for Calculation, set Limit Iteration to checked, Maximum iterations 100, and Maximum change .000,000,000,000,001 without the commas.
Create a new worksheet in Excel titled Goal Seeking - Neutral Operations, or something reasonably similar.
Set Preferences: Open Preferences in the Excel menu.
The problem is to figure out a+b=a*b = c where a = πR^2 and b = πr^2.
In rows 1, enter the column headings.
Enter values and formulas in row 2.
In cell D2, enter the formula w/o quotes "=(PI()*B2^2)/((PI()*B2^2)-1)".
In cell F2, enter "=D2".
Select columns B and H and do Format Cells Number Number Decimal Places 15.
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