The figure below shows a rectangle abcd having diagonals ac and db: a rectangle abcd is shown with diagonals ac and bd. anastasia wrote the following proof to show that the diagonals of rectangle abcd are congruent: anastasia's proof: statement 1: statement 2: ab = dc (opposite sides of a rectangle are congruent) statement 3: ac2 = db2 (from statements 1 and 2) statement 4: ac = db (taking square root on both sides of ac2 = db2) which statement below completes anastasia's proof? in triangle adc and bcd, ab = dc (opposite sides of a rectangle are congruent) in triangle adc and bcd, ab = dc (opposite sides of a rectangle are parallel) in triangle adc and bcd, ad = bc (opposite sides of a rectangle are congruent) in triangle adc and bcd, ad = bc (opposite sides of a rectangle are parallel)