Question

QUICK HELP

Answer 1

Thinking out loud...
let the center point be O
if AC is the diameter then so must be DB because it passes through the midpoint
this means angle DOC must be 120 (vertical angles) and the triangle DOC must be isosceles. so the other two angles must be 30 so the triangle adds to 180
so I guess angle BDC must be 30
I think...

Answer 2

yes 30 degrees is correct

Answer 3

yay! I love it when I have no idea what I'm doing and get the right answer anyway!
thanks jimmy!

Answer 4

thats ok - i got it wrong a minute a go and had to do an embarassing re-check

Answer 5

In the future, please do not repost your question so quickly. jimmyrep fixed his answer on your other post before TuringTest answered it correctly here, so you just added a pointless question to the list. Thanks!