Firstly, the connection between Revelation 12 and Daniel 7 must be noted. In Daniel 7 we find a beast revealed to Daniel in a vision, which appears very much like the beast of Revelation 12:
7 After this I saw in the visions by night a fourth beast, terrifying and dreadful and exceedingly strong. It had great iron teeth and was devouring, breaking in pieces, and stamping what was left with its feet. It was different from all the beasts that preceded it, and it had ten horns.
3 Then another portent appeared in heaven: a great red dragon, with seven heads and ten horns, and seven diadems on his heads.
The similarity of these two beasts is significant, especially given the context of Daniel’s vision, in which empires are represented by beasts:
15 As for me, Daniel, my spirit was troubled within me, and the visions of my head terrified me.
16 I approached one of the attendants to ask him the truth concerning all this. So he said that he would disclose to me the interpretation of the matter:
17 “As for these four great beasts, four kings shall arise out of the earth.
23 This is what he said: “As for the fourth beast, there shall be a fourth kingdom on earth that shall be different from all the other kingdoms; it shall devour the whole earth, and trample it down, and break it to pieces.
The explicit interpretation of the angel is that these beasts represent empires, with the fourth beast representing the fourth empire on earth. The vision in Daniel 7 is related directly to the vision of the image in Daniel 2, in which four empires were represented by the four metals of the image of a man.