Intensity of an electric field $$\left( E \right)$$ depends on distance $$r$$ due to a dipole, is related as

Solution :
Field intensity on axial line of electric dipole is given by
$$E = \frac{1}{{4\pi {\varepsilon _0}}} \cdot \frac{{2p}}{{{r^3}}}\,......\left( {\text{i}} \right)$$
and electric field at equatorial position is given by
$$E = \frac{1}{{4\pi {\varepsilon _0}}} \times \frac{p}{{{r^3}}}\,......\left( {{\text{ii}}} \right)$$
where, $$p$$ is electric dipole moment.
From Eqs. (i) and (ii), we get
$$E \propto \frac{1}{{{r^3}}}$$