Final answer:
Walking halfway around a circular lake from a starting point creates a 180° angle at the center of the lake.
Step-by-step explanation:
If a woman starts at point A on the shore of a circular lake and walks halfway around the lake, she will make a 180° angle at the center of the lake. To visualize this, imagine the lake as a circle and the woman's path as the diameter of that circle. Walking halfway around the lake would mean traversing from one point on the circumference to the exact opposite point, which corresponds to a straight line through the center of the circle, creating a 180° angle.