Geometry:

The 2p_y orbital has the general dumbbell shape. Each one of the sp² hybridized orbitals comprises a deformed dumbbell shape identical to a sp³ hybridized orbital. Though, the variation among the sizes of the major and minor lobes is larger for the sp² hybridized orbital. The hybridized orbitals and the 2p_y orbital occupy spaces thus far separate from each other as possible. The lobes of the 2p_y orbital comprise the space above and below the plane of the x and z axes. The three sp² orbitals (major lobes displayed only) will then occupy the remaining space like that they are as far separate from the 2p_y orbital and from each other as possible. The result of it is that, they are all located in the x-z plane pointing in the direction of the corner of a triangle (trigonal planar shape). The angle among each of these lobes is 120°. We are now ready to look at the bonding of a sp² hybridized carbon.

Figure: (a) Geometry of the 2py orbital; (b) geometry of the 2 py orbital and the sp2 hybridized orbitals.