We know from basic geometry that the sum of angles about a point is always [tex] 360^{\circ} [/tex]. Thus, in our case too this will remain the same and hence the angle will remain [tex] 360^{\circ} [/tex].
Therefore, when tiles are tessellated in a plane, the angle measure sum that is required of the tiles surrounding a single point is always [tex] 360^{\circ} [/tex].