The wall's corner sectors were all assumed to have a square base and all be the same size in the calculations. In order to calculate the volume of the corner sectors, each sector was divided into one of four geometric shapes:
Rectangular prism
Square prism
Pyramid
Triangular prism
The volume of the rectangular prisms was calculated by multiplying the height of the fort, H, the depth of the inside of the slope, I, and the length of the flat top, T. (Vol = H*I*T).
The volume of the square prisms were calculated by multiplying the height of the fort, H, by the square of the length of the flat top, T, (Vol = H*T^2).
The volume of the pyramids was calculated by multiplying 1/3 by the height of the fort, H, and the square of the depth of a slope, I, (Vol = (1/3)*H*I^2).
The volume of the triangular prisms was calculated by multiplying (1/2) by the height of the fort, H, the depth of the outside slope, O, and the quantity of the depth of the inside slope, I, plus the length of the flat top, T, (Vol = (1/2)*H*O*(I + T)).
The total volume of the sector is found by adding the volumes of the geometric regions. TotalVolume = (2*RectPrism) + (SquarePrim) + (2*InnerPyramid) + (2*TriangularPrism) + (SmallPyramid)).

Minimum Estimate 
Maximum Estimate 
H (Height of Fort) 
5.2 
5.5 
I (Depth of Inside Slope) 
5 
5.1 
T (Length of Flat Top) 
1.8 
2.1 
O (Depth of outside slope) 
2.1 
2.3 
Rectangular Prisms 
46.8 
58.905 
Square Prism 
16.848 
24.255 
Inner Pyramids 
43.33333 
47.685 
Triangular Prisms 
37.128 
45.54 
Small Pyramid 
7.644 
9.698333 
Volume of sector 1 
279.0147 
338.2133 
Total Volume 
1674.088 
2029.28 