Question

how do I prove that angles subtended at the centre of a circle by a chord is double the size of the angle which the same chord subtends at the circumference. I have the diagram with me.

Answer 1

if the subtended angle that touches the circumference is more close to B in your diagram the line cannot pass through centre from the circumference angle

Answer 2

In your diagram if join AB it must be parallel to

Answer 3

We know that angles in the same segment are equal. So using my diagram, and then knowing this property, we can prove it.

Answer 4

thanks