When a light is incident at polarising angle, the reflected and refracted rays are perpendicular to each other as shown in the figure,
where $i_p$ is the angle of incidence and $r$ is the angle of reflection, $r'$ is the angle of refraction.
Given, $i_p = 57.5^{\circ}$
Let $\theta$ be the angle between the incident ray and the refracted ray.
From figure,
$\theta = i_p + r + 90^{\circ} $
$= 2i_p + 90^{\circ}$
$ = 2 \times 57.5^{\circ} + 9.^{\circ}$
$ = 205^{\circ}\quad [\because i_p = r]$
