`H_(2)O` molecule is a triatomic molecule but its geometry is not linear. Why ?

H_(2)O molecule is linear

what is triatomic molecule?

An example of triatomic molecule is

Give an example of triatomic molecule.

CO_(2) and H_(2)O both are triatomic molecules but their dipole moment values are different. Why?

CO_(2) and H_(2)O both are triatomic molecules but there is large difference in their dipole moment values. Explain.