We can always split a regular polygon with 
sides into triangles, whose base is the side of the polygon and whose height is the apothem of the polygon. So, the sum of the areas of all these triangles is
where is the number of sides, 
is the side length, and 
is the apothem length.
So, you just need to plug you values in: in your case, you have 
So, the formula becomes
The second one is 35 and the 3rd is 6:7 ratio
Darren's model is wrong because he multiplied the fractions when he should have subtracted.
4/5 • 1/2 = 4/10
4/5 - 1/2
8/10 - 5/10 = 3/10
The correct model would be 3/10.
2(x-1)^2 is the final answer
Factorize the numerator and denominator. You'll see that they both have a factor of 4 that can be canceled. The introduce a factor of 3 to change the denominator to 36.
