Where to Sit (II)? – Exploring Inscribed Angles Intercepting the Same Arc

① This dynamic geometry activity demonstrates that inscribed angles intercepting the same arc in a circle are congruent, a key theorem in circle geometry. ② Core concepts include inscribed angles, central angles, arcs, and the inscribed angle theorem (angles subtending the same arc are equal, and each is half the central angle). ③ Construction uses GeoGebra commands: Circle to draw the circle, Point to place points O, B_1, B, A on or inside the circle, Segment to connect points, and CircleArc to highlight the intercepted arc. By dragging points, students observe that the angle measures remain equal. ④ Suitable for middle school (grades 8-9) or high school geometry classes, ideal for inquiry-based learning or as a visual proof before formal theorem introduction.