Which bonds are formed by a carbon atom with `sp^(2)` hybridization

Which bonds are formed by a carbon atom with sp^(2) -hybridisation ?

Which bonds are formed by a carbon atom with sp^(2) -hybridisation ?

Which bonds are formed by a carbon atom with sp^(2) -hybridisation ?

The bond angle around atom which uses sp^(2) hybridization is :

If in diamond, there is a unit cell of carbon atoms as fcc and if carbon atom is sp^(3) hybridized, what fractions of void are occupied by carbon atom.