Yeah, it's something to do with the fact that the area required is pi(R^2 - r^2), where R is the radius of the tower and r is the radius of the column. The area appears to end up being multiples of pi, and the factor is (chord length/2)^2 (from the answer SimonAh gave)
Yeah, it's something to do with the fact that the area required is pi(R^2 - r^2), where R is the radius of the tower and r is the radius of the column. The area appears to end up being multiples of pi, and the factor is (chord length/2)^2 (from the answer SimonAh gave)
Haven't quite worked out why.