In a trigonal structure how does the double bond affect the angle between the two single bonds?

Question

In a trigonal planar structure such as CH2O molecule, with one double bond and two single bonds, how does the double bond affect the angle between the two single bonds?

Answer 1

The double bond has higher electron density than a single bond. Thus the double-bond -single bond repulsions are greater than the single bond -single bond, making the single bond -single bond angle smaller than either of the 2 double bond-single bond angles and thus smaller than 120 deg.