How did cleopatria die?

We don't know. There's a myth that she died by snakebite, but there are too many holes in that story. Even the ancient writers, were skeptical of the snakebite idea. Augustus actually perpetrated the myth for his own purposes and William Shakespeare gave it another boost and it's been with us ever since. The closest guess we can make is that it was some type of poison, as Cleopatra was said to be knowledgeable about poisons.