What two attributes have been used to sort these shapes? A. Shapes with perpendicular sides and shapes without perpendicular sides

B. Shapes with parallel sides and shapes without parallel sides

C. Shapes with equal sides and shapes with unequal sides

D. Shapes with equal angles and shapes with unequal angles

Given: in quadrilateral wxyz , and bisect each other at point a. prove: quadrilateral wxyz is a parallelogram. statement reason 1. and bisect each other. given 2. wa = ya xa = za definition of bisection 3. m∠yaz = m∠xaw vertical angles theorem 4. sas criterion for congruence 5. ∠ ywx ≅ ∠wyz corresponding angles of congruent triangles are congruent. 6. || converse of alternate interior angles theorem 7. m∠xay = m∠zaw vertical angles theorem 8. ∆xay ≅ ∆zaw sas criterion for congruence 9. ∠xzw ≅ ∠zxy corresponding angles of congruent triangles are congruent. 10. || converse of alternate interior angles theorem 11. quadrilateral wxyz is a parallelogram. definition of parallelogram what is the missing statement in this proof? what is the missing statement in this proof?