The 4th apparition angers Macbeth because he sees that Banquo's kids are gonna be king and he gets mad because he killed Banquo and the propecy is still going to go on and his kids will get nothing.

What are the 4 apparitions in Macbeth?

The First Apparition: "Beware Macduff; Beware the Thane of Fife." The Second Apparition: "none of women born Shall harm Macbeth." The Third Apparition: "be lion-mettled, proud, and take no care who chafes, who frets… until Great Birnam wood to high Dunsinane Hill /Shall come against him [Macbeth]."

Why is Macbeth so angered at the sight of the last apparition?

Macbeth wants to be free of the witches prophesies and doesn't want to die. He is angry of his choices.