1. Area of the Pins...

#8.

2. I'm sorry to say, but that does not seem correct.

If there are three sections then we have a total of 4 x's.

Code:
   _______________________________________________
|               |               |               |
|               |               |               |
|               |               |               | x
|               |               |               |
|               |               |               |
y
So:
P = 100 = 4x + 2y --> y = 100/2 - 4x/2 = 50 - 2x
A = x*y = x(50 - 2x) = 50x - 2x^2

A' = 50 - 4x
A' = 0 = 50 - 4x --> x = 50/4 = 12.5

P = 100 = 4(12.5) + 2y --> y = (100 - 50)/2 = 25
A = (12.5)(25) = 312.5

3. Re:

Thanks EcMathgeek for catching the error. I was right, I just messed up on the wording when I was entering it into the computer ( I was up to late). Here is what I meant to say...