I have an illustration in my book of a quadrilateral inside a circle. The quadrilateral is ABCD; AB is a vertical line and then AC and BD are the same length, but AC slopesd downward and BD upwards. Finally, there's CD; it's not vertical, as it slopes upward from D to C and is shorter than AB. The question is how are angles BAD and BCD related?

Question

I have an illustration in my book of a quadrilateral inside a circle. The quadrilateral is ABCD; AB is a vertical line and then AC and BD are the same length, but AC slopesd downward and BD upwards. Finally, there's CD; it's not vertical, as it slopes upward from D to C and is shorter than AB. The question is how are angles BAD and BCD related?
I think it has something to do with triangles, but I can't quite find the relation.
I know this is probably really confusing, but I tried drawing a picture of it on paint and when I went to post it, it said I cn't post websites; please help me, I really don't get it.

Reiny · Answer

If a quadrilateral inside a circle has its 4 vertices on the same circle, then it is a cyclic quadrilateral.
One of the properties is that opposite angles add up to 180º

I think this is the relationship you are looking for according to your description.