Answer
Bond angle 3 is around 109.5 degrees, and bond angle 4 is less than 109.5 degrees.
Work Step by Step
Carbon has no lone pairs but is bonded to four atoms. Because there is a tetrahedral electron geometry and are no lone pairs, the bond angle is approximately 109.5 degrees for bond 3. Meanwhile, the central atom in bond 4, oxygen, has two lone pairs and is bonded to two atoms, so it has a tetrahedral electron geometry with a bond angle of less than 109.5 degrees.
