  After having investigated the geodesic triangles and their angle sums in Nil
and $Sl\times\mathbb{R}$ geometries we consider the analogous problem in Sol
space that is one of the eight 3-dimensional Thurston geometries. We analyse
the interior angle sums of geodesic triangles and we prove that it can be
larger than, less than or equal to $\pi$. Moreover, we determine the equations
of Sol isoptic surfaces of translation-like segments and as a special case of
this we examine the Sol translation-like Thales sphere, which we call Thaloid.
We also discuss the behavior of this surface. In our work we will use the
projective model of Sol described by E. Moln\'ar in \cite{M97}.
