There isn't a fixed number of stars that make up a constellation. Constellations are simply patterns of stars as seen from Earth.

While there are some bright, prominent stars that define the shape of Cetus, the constellation actually encompasses a vast area of the sky. This means that there are many, many more stars within the boundaries of Cetus that we can see, depending on the clarity of the night sky and the power of our telescopes.

So, there's no single answer to how many stars are in Cetus!