1. **State the problem:** We are given a circle with center P and diameter AB. Point C lies on the circle such that the angle formed by lines PC and PB is 41°. 2. **Understand the geometry:** Since AB is a diameter, angle APB is 180° because it's a straight line. 3. **Find the arc measure of minor arc AC:** The angle at the center (P) subtending arc AC is given as 41° (angle between PC and PB). 4. **Recall that the measure of the arc corresponds to the central angle:** Therefore, the measure of the minor arc AC is equal to the central angle $\angle CPB$, which is 41°. **Final answer:** The measure of the minor arc AC is $41^\circ$.