Ihave forgotten how to answer this question

Check the picture below.

so, as you see there, those radius make out an "equilateral triangle", and as you know, all angles in an equilateral triangle are 60° each.

now, if we make out the other equilateral triangle underneath that one, and add up the angles making out ∡CBD, you'd get, yes, you guessed it.

Where’s the problems ? ?