The properties of mosaic pentagons with a pair of equal adjacent edges

It was obtained by O.G. Bagina the complete classification of convex mosaic pentagons, admitting normal (edge to edge) tilings, in 2011–2012. The classification includes 8 types of such pentagons. In the proof of the completeness of this list the following fact was used. If a convex pentagon tiles the plane normally, belongs only the first type of the list and has only a pair of equal adjacent edges, that is, the angles and edges of this pentagon satisfy the relations $C_0 = C_1, x_2 + x_3 = 180^\circ$, then it angles satisfy also the relation $x_0 + 2x_1 = 360^\circ$. But this statement has not been proven. This paper fills this gap.