Circle geo (1 Viewer)

[Joshmosh2]

If I have already proven that a shape is a cyclic quadrilateral, where would the centre of the created quad be?
I recall somewhere that the centre is the intersection of altitude lines (perpendicular to opposite sides of shape).
I was also thinking that the angle at the centre would be twice the angle at the circumference, but would that mean i would have to measure the angles to find the centre? is there an easier way?

 

[Carrotsticks]

If I have already proven that a shape is a cyclic quadrilateral, where would the centre of the created quad be?
I recall somewhere that the centre is the intersection of altitude lines (perpendicular to opposite sides of shape).
I was also thinking that the angle at the centre would be twice the angle at the circumference, but would that mean i would have to measure the angles to find the centre? is there an easier way?

From each side, draw a perpendicular bisector. Since you've got a cyclic quadrilateral, these perpendicular bisectors will be concurrent at the centre of the circle that circumscribes the quadrilateral you've got (called the circumcentre).