The 6 angles with vertex P are:
- Angle APB
- Angle APC
- Angle APD
- Angle BPC
- Angle BPD
- Angle CPD
The letter P must be in the middle since this location is the vertex. Something like angle BPA is the same as angle APB. We can swap the order of the outer letters without any change to the angle itself. Effectively, this means each angle has two possible names.