# Math Help - I need help with these geometry please?

2. ## Re: I need help with these geometry please?

What does the notation with two letters and the curved line on top mean?

3. ## 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?

4. ## 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