First, the difference in travel distance that the blade must travel to hit the object (tube) if you change the size of the blade from big to smaller (assuming the center of the blade is always fixed). This difference is shown as DELTA in the picture.

Second the X distance of the cutpoint (where blade hit object) to center of the blade (X2)

Third the Y distance of the cutpoint (where blade hit object) to center of the blade (Y2)

Could someone please show me a mathematical formula that relates to the diameter or radius would represent these values. Thanks in advance.