What is "Pouling Equation" and How to calculate % ionic character of covalent bond ?

The "Pouling Equation" of % Ionic Charater of covalent compound given as"

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What is" Haney and Smith Scale" and How to use calculation of % ionic character of covalent bond ?

How to calculate the & ionic character in H-X bond of Halogen acids.Given that electronegativity of H ,F, Cl, Br. and I are 2.1, 4.0, 3.0, 2.8,and 2.5 respectively.

Calculate the % of ionic character of a bond having length is 0.83 Å and 1.82 D as its observed dipole moment?