55. 如下圖所示，圓鼻刀（刀徑10mm，圓角2mm)與半圓柱曲面（半徑25mm)的接觸點為P，則刀端中心 Q 之座標為(A)X26.182 Z11.6(B)X26.382 Zl 1.5(C)X26.082 Zl 1.7(D)X25.982 Z11.8。 (sin30° = 0.5, cos30° = 0.866, tan30° = 0.5774)