>>662
赤線内(全体)のとき
S = 2π + (3/2)√3 = 8.88126152
X = ((8/3)π + (9/4)√3) / S = 12.2756947 / 8.88126152 = 1.38220169
Y = 0,

黒抜きのとき
S = π + 3√3 = 8.33774508
X = (8π/3 + 9√3) / S = 11.9840188 / 8.33774508 = 1.437321325
Y = 0,
>>681 とほぼ一致