Consider the paragraph proof. given: d is the midpoint of ab, and e is the midpoint of ac. prove: de = bc it is given that d is the midpoint of ab and e is the midpoint of ac. to prove that de is half the length of bc, the distance formula, d = , can be used to determine the lengths of the two segments. the length of bc can be determined with the equation bc = , which simplifies to 2a. the length of de can be determined with the equation de = , which simplifies to $$. therefore, bc is twice de, and de is half bc. which is the missing information in the proof?