54 ! explaingiven: parallelogram abcd, ab = ad, and ac⊥bd. which statement can be proved? a. abcd is a rectangle, but not necessarily a square. b. abcd is a parallelogram, but not necessarily a rhombus. c. abcd is a rhombus, but not necessarily a square. d. abcd is a square.

C.  ABCD is a rhombus, but not necessarily a square.

Step-by-step explanation:

A parallelogram with adjacent sides congruent is a rhombus, which also happens to have perpendicular diagonals (that bisect each other). If the diagonals are different length, then the parallelogram is not a rectangle, so the rhombus is not a square.

investment b is an ordinary annuity with $3,909.64 in the account after one year.

step-by-step explanation: