Theorem 1.6 Angle at Centre Twice Angle at Circumference
Instruction
Drag the point B to observe the relationship between and .
Answer the following questions : (You can drag the points in the figure to help you)
If reflex AOB is , = ____.
If AOB is , = ____.
The last question gives a proof of Theorem 1.7 Angle in semi-circle
Please note that the converse of Theorem 1.7 is also true.