# I need help with these geometry please?

• Aug 17th 2011, 06:02 PM
zokura
I need help with these geometry please?
• Aug 17th 2011, 06:18 PM
Prove It
Re: I need help with these geometry please?
What does the notation with two letters and the curved line on top mean?
• Aug 18th 2011, 12:48 AM
Opalg
Re: I need help with these geometry please?
Let $O$ be the centre of the circle. The information $\widehat{CD}=55^\circ$ tells you that $\angle COD=55^\circ.$ Now use the theorem that the angle at the centre is twice the angle at the circumference to find $\angle DBC.$ Can you see how to continue the problem from there?
• Aug 22nd 2011, 10:37 AM
bjhopper
Re: I need help with these geometry please?
Hi zokura,
This is what you need to know

angle between secants = 1/2( far arc - near arc)
angle between chords =1/2 the sum of arcs created by each equal vertical angle