The hybridisation of the carbon atom in methane is

Explanation

One 2s and three 2p orbitals mix to give four equivalent sp3 hybrids directed to the corners of a tetrahedron, which explains why all four C-H bonds are identical and the angle is 109.5 degrees. Without hybridisation the s and p orbitals would give bonds of different strengths and 90 degree angles, which contradicts experiment. Counting four electron regions is the quickest route to sp3.