Use the drop-down menus to complete the paragraph proof. we are given that xy is parallel to zw. if xz is a transversal that intercepts xy and zw, angle and angle are alternate interior angles. since xy is parallel to zw, we know that these angles are . we also know that angle xvy and angle zvw are angles, and thus congruent. we can conclude that △xyv ~ △zwv using the similarity theorem.