On the circumference of a circle, if an arc equal in length to the radius of the circle is marked off, then the arc will subtend, at the center of the circle, an angle of 1 radian. The angle ? (or POB ...

1. (Prove) Equal chords of a circle subtend equal angles at the center and (motivate) its converse. 2. (Motivate) The perpendicular from the center of a circle to a chord bisects the chord and ...

(b) Arc and chord properties: If two arcs subtend equal angles at the centre, they are equal, and its converse. If two chords are equal, they cut off equal arcs, and its converse (without proof).

Bees enter through the front (bottom of diagram) and are faced with two maze arms. At the decision point, the two stimuli subtend a fixed visual angle. The bee must enter the correct arm of the maze ...