Find the measure of angle x in the figure below: Two triangles are shown such that one triangle is inverted and they share a common vertex. The lower triangle has two angles at the base. The lower left angle is marked as 45 degrees. The lower right angle is marked as 55 degrees. The angle at the vertex of the inverted triangle at the top is marked as x degrees. The angle at the vertex of the bottom triangle is marked as y degrees.

Group of answer choices

45°

80°

55°

100°