1. **State the problem:** We have a circle with center P, with diameters AC and BD. The angle between radii PA and PD is given as 155°. 2. Since AC and BD are diameters, point A is opposite C and point B is opposite D on the circle. 3. The two diameters divide the circle into four arcs: AB, BC, CD, and DA. Because AC and BD are perpendicular diameters (their intersection is the center), each of the four arcs corresponds to a central angle summing to 360° total. 4. However, the problem states that the angle between radii PA and PD (one from diameter AC and the other from BD) is 155° instead of 90° as in perpendicular diameters. This means the diameters are not perpendicular but intersect at 155°, so the arcs are affected. 5. The total circle is 360°, and since angle APD = 155°, the angle CPB (opposite angle) equals 360° - 155° = 205° (since diameters form chords, opposite central angles sum to 360°). 6. Minor arc BC subtends central angle CPB, so its arc measure is 205°. 7. But we need the minor arc BC, so we take the smaller arc between points B and C. Since 205° > 180°, the minor arc BC is the remaining arc, which is 360° - 205° = 155°. **Final answer:** The arc measure of minor arc BC is $$155^\circ$$.