The four angles are the Ascendant, Descendant, IC and MC. If one has one of the modalities on one angle, he has the same one on ALL the angles, In other words, if you have a Cardinal Sign on the ASC, you will have Cardinal signs on the other Angles. One can ascertain certain traits, based on the modality on the Angles. If one has a Cardinal sign on the Angle, one will tend to be a leader. The Cardinal signs are Aries, Cancer, Libra and Capricorn.
If one has a Fixed Sign on the Angles, one will tend to be stubborn, but this will give stability to the personality. The Fixed Signs are Taurus, Leo, Scorpio and Aquarius.
If one has Mutable Signs on the Angles, one will tend to be flexible and adapt to change, easily. However, the person may not feel as strong of a sense of identity as the other two. The Mutable Signs are Gemini, Virgo, Sagittarius and Pisces.