3. Angles Subtending the Same Arc
Points A, B, C and D all lie on the circumference of the circle. Some of the points are connected by chords as shown. Point I is the intersection of chord CB and AD.
What do you notice about and ?
Move around points C and D. What impact does this have on the two angles?
Can you infer the relationship between and ?
Mark the check box and move around the points to confirm the relationship between the two angles.
Given what you know about the angles, what can you deduce about and ?