Please answer me as soon as possible....................................... ........................

Dear student,

For finding out the dipole moment of the whole combination, there are two ways in this case-

1. You can split the ‘2q’ charge at point B into two charges, each with charge ‘q’.
One of these charges can form a dipole of magnitude ‘qd’ along side BC with the charge on C, and the other one forms dipole of same magnitude but in the direction of side AB with the charge of point A. These two dipoles can be vectorically added to obtain net dipole moment of magnitudealong the line joining point B and the mid-point of side AC.

2. The twocharges on A and C can be considered to reside at the mid point of side AC effectively with a charge. Hence the net dipole moment will become
alongthe line joining point B and the mid-point of side AC.